From Artifacts to Zwiebacks. Bandagoran magic items of note

Al-Kuin (artifact). History: Envious of Hecate's success in becoming a major goddess by giving men the gift of magic, Kali turned to Haskeem, the Land of the Sun, far to the south of Bandagora. Here She tried to create a hatred of magic so great that the people of Haskeem would first root out all magic in their own lands, then wage holy war (jihad) against Bandagora until all use of magic was banned there too. She seemingly gave the gift of magic to some of her worshipers, the Cabal, encouraging them to call themselves gods as they commanded the powers of magic. Kali's bold plan failed. The Cabal did come into power and grew to be feared and hated, as the plan intended, but their rule was too quickly put to an end and their blasphemy associated with the Cabal, not with the use of magic. See the excerpt from Kali's Gambit by Khalenden. To destroy the Cabal some twelve or thirteen swords, perhaps one or two daggers, were forged. Many were scimitars, one or two a khopesh, and at least one was indistinguishable from a longsword (Grimslade). All were dedicated the fight against magic-users. One of the blades was Al-Kuin, a short sword.
Phase One. The sword is +3. It inflicts double damage on an unmodified 20. Any non-magical missile can be deflected if the wielder rolls a 1 on a d6. Once per day the wielder can awaken the spirit of the sword. This lasts 1 round per level of the wielder and gives him -1 on initiative (a bonus). Furthermore, if he sustains damage during that time, he may reflect the damage back on the inflicter. If it is a melee attack, he must roll his unmodified THAC0. If successful, the hit points are subtracted from the original attacker. If it is a spell, he must save versus spells. If successful, the spell caster must save against the spell (if possible) or suffer the effects himself. Activating the spirit gains him one "artifact point".
Phase Two. This phase is basically equal to phase one except that the wielder gains an extra -1 to his AC when he wields the sword. He may activate the spirit twice per day, the duration is 2 rounds per level, the initiative bonus is -2 and he may reflect two attacks during each of the awakenings.
Phase Three. The sword is +3 to hit, +4 to damage. At this stage the character cannot benefit from wizard spells (such as strength), they have no effect. He cannot use a shield, but Al-Kuin gives him a -2 AC modifier and ensures him a maximum AC of 3 at all times (if wielded). He has a Magic Resistance of 0% (if you play 2nd Ed. or later, this may seem worthless, use 20% instead). He has a 2 in 6 chance of deflecting non-magical missiles, and a 1 in 6 chance of deflecting magical ones (magical arrows, magic missiles, chromatic orb, etc.) in addition to his Magic Resistance. The awakenings work as per phase two, except that the initiative bonus is -3.
Phase Four. The sword is +4. The character's Magic Resistance increases to 10%. Though the spell caster may be high-leveled, the chance of spell failure cannot go below 10% (use 35% in 2nd Ed.). This Magic Resistance works on any spell in which the wielder is within the area of effect, whether cast by friend or foe. He may activate the spirit three times a day, the duration is 2 rounds per level, the initiative bonus is -4 and he may reflect up to three attacks during each of the awakenings. His AC cannot be above 2. He has a 3 in 6 chance of deflecting non-magical missiles. A 2 in 6 chance of deflecting magical missiles, and a 1 in 6 chance of deflecting any flung magic, such as fireball or slow. Deflecting a spell means it dissipates harmlessly, if it fails, there's still his Magic Resistance. The character now sees it as his primary duty to banish the use of magic. Enemy wizards will be killed, neutral ones dismembered or neutralized in some other fashion. Friendly wizards such as those in the wielder's party will be tolerated at first. Typically the wielder will seem to be making an exception on the merit of their friendship. A tentative truce that may go on for a while, until the day the wizard finds himself recovering from having been brought to zero hit points by an enemy attack. He will discover his spell book missing and will be informed by Al-Kuin's owner that he (the wizard) will be a much greater hero without it.

Artifacts. Comments: Artifacts should be placed into two categories: Those that should be handled by the players, and those that shouldn't. You don't need too specific rules for the second category. The player characters may recover it and return it to its rightful place, but they shouldn't really use it. If they do, the DM can simply rule some divine omen or intervention.
But players love the first category (at least my players do). They love the temptation, the corruption and most of all the raw power. In my humble opinion, most of the items in The Book of Artifacts are not very tempting (seriously, A Holy Avenger is more powerful than some of those). They don't have enough interesting powers, and the curses work too quickly. In my view, artifacts should be useful (not too powerful) but relatively safe at first, luring the character to use it more. Then the powers should increase, hooking the character. Finally, when the full powers of the artifact is revealed, the character is reduced to a vessel for the artifact.
General Rule: The relationship between the character is divided into 4 phases. Each time the item is used in a certain way, the artifact gains one point towards control. The phases are normally the following:
Phase One. Points less or equal to Character level. Character in control.
Phase Two. Points less or equal to 3 times Character level. Character dominant.
Phase Three. Points less or equal to 5 times Character level. Artifact dominant.
Phase Four. Points more than 5 times Character level. Artifact in control (goodbye).
If used properly, the character should be curious in phase one, have fun in phase two, then begin to have second thoughts in phase three, and finally get rid off the artifact with the help of his friend just as he has entered phase four.
I use the term artifact rather loosely, in fact they could equally well be called 'cursed items', and this means that Bandagora is practically brimming with artifacts. Many are created by a god, but some are simply powerful beings somehow stored in an item. See Dragon Mask and Death Blade.

Belt of Strength. By tightening this belt, the wearer gains the maximum natural Strength possible (i.e. 18/00 for male humans and 18/50 for female humans). The belt can be tightened once per day and the effect lasts for one round per level of the user.

Blood Brother (sword). History: The legend tells of a great battle between Vikings and Varnasir. The Vikings were outnumbered and prayed to Modi for help. They had nothing to sacrifice but their own blood. But Modi accepted their sacrifice and made their swords into 'blood brother's - able to bleed for the Vikings. The legend states that there were 5 swords. A short, a long, a bastard, a broad, and a two-handed sword. Why this so, no one knows.
Game effects: A Blood Brother sword is +3, and effectively doubles the wearer's hit points. If a fighter with 20 hp finds a Blood Brother sword, he will still have 20 hp, but he could heal or rest up to a maximum of 40. The owner must remain in physical contact with the sword, but it may be sheathed. If not, the extra hit points are temporarily lost (simply half wearer's hp, round up). if contact is broken for a day (24 hours), the hp are lost, but may be regained through healing, if the sword is recovered. Finally, the sword can 'die' for its owner. If one attack (not necessarily a melee attack) 'kills' the owner, the sword becomes non-magical, but the attack has no other effect on the owner. For example, a fireball spell causing a maximum damage of 44 hp explodes on top of the owner. He has 40 hp (20 hp of his own), and fails his save. He is now left with a non-magical sword and has 20 hp.
Some hopeful scholars believe that the actual swords are reincarnations of some ideal swords. This means that even if the Blood Brother two-handed sword died for Kernla in 1105, it may reappear later as another two-handed sword.

Bracelet of Etherealness. This porcelain bracelet is a popular Kartrian item favored by low-level nobles. If smashed against a hard surface, it will break and make the former owner ethereal for about one hour. Though it is expensive and useable only once, many nobles fearing adventure-type troublemakers wear these amulets. They are available in three different styles: male, female and discreet.

Death Blade (artifact). History: The origins of the blade are unknown. It is attributed to Nergal, but the relationship is uncertain. Most recently (1113) is was employed by the desperate villain Dorman "the Raven". While awaiting trial in Enkisborg he was freed by the Brotherhood of Doom and given the blade as a means of getting speedily equipped. In the end, it meant his irrecoverable doom as a determined band of adventurers caught up with him.
The blade typically looks like a longsword, but it will shape itself to conform to any one-handed sword or sword-like weapon such as a saber or a scimitar. Its most spectacular ability is that of animating defeated opponents. The wielder can animate one creature. The undead acts as a juju zombie with the hit dice of the deceased, but the hit dice is decreased by 1 per day animated. The sword will always know what creature has the highest hit dice.
Phase One. The blade is +3. A natural 20 drains one level and the person hit must make a System Shock Roll or die on the spot. The wielder has immunities as if he were a zombie (charm, sleep, hold, cold). 1 point per hit in combat (3 points for a "20"). These points apply to all phases.
Phase Two. The blade is +4. On a "20" the wielder gains the hit points drained. Furthermore, on all other hits the wielder has 10% vampiric regeneration. The wielder is not affected by illusions. At this point (and in Phase Three), each combat temporarily stores 1 hit point in the blade. If the blade is kept, it means nothing until all the character's hit point are stored in the blade. When this happens, go to Phase Four. If the owner gets rid off the blade, the points are lost but may be healed at 10% of the normal rate.  
Phase Three. The blade is +5. A "20" still drains a level, but also works a slay living spell (the wielder gains all hit points lost by victim). Furthermore, on all other hits the wielder has 20% vampiric regeneration. The wielder is not affected by poison or paralysis. The animated creature does not deteriorate 1 hit die per day. The wielder must kill at least one person ("charmable" being) a week or temporarily lose one level (per week). The levels lost are regained immediately upon killing the person. If the sword is ditched, the loss is permanent, but hit points lost from this account are deducted the hit points stored in the blade.
Phase Four. The owner is now immune to lightning. He will try to kill all humans and animate them. He can animate any number of beings.

Dragon Blood (potion). A dragon is a magical and powerful beast. When it dies, the body has many uses, and so its blood. If tapped while the body is still warm, the blood can be made into a wondrous potion, allowing the imbiber to gain some of the dragon's powers.
Game effects: A dragon can supply a number of potions equal to its hit dice. At least one pint of blood must be tapped for each potion, but tapping all the blood will not give any further benefits for this purpose. If treated properly (see below), the blood can be turned into a special potion that allows the drinker to cast spells as a natural spell caster (i.e. a monster). Each potion works for 24 hours and enables the imbiber to cast one specific type of wizard spell. The spell could be any spell, but would be most likely to be either a spell the dragon were able to cast, or a spell that resembles the spell-like abilities of the dragon. Blue dragon blood could enable the drinker to cast shocking grasp, lightning bolt perhaps chain lightning. The same spell could appear several times, but the potions generally give different powers. The level of the spell should not be much higher than the spells the dragon could cast. There should not be any expensive or rare components. When casting the spell, the imbiber loses a number of hit points equal to the level of the spells. Apart from that and the 24 hours, there is no limit to the number of times that he could cast that spell. The DM may invent his own spell-like power and then assign it a hp cost. The blood must be prepared in some mysterious manner. Either the party can bring the blood to an alchemist. He will demand half the blood, but will usually let the party keep the interesting spells (perhaps the alchemist can find use for a potion that gives the ability to cast pyrotechnics). Or the DM can invent a quest.

Dragon Mask (artifact). History: According to legend, a young merchant from Ditmar wanted to do trade with dragons. He knew that a great many dragons lived on the Troll Isles. He prayed to Plutus that he might talk with the dragons and one day found the mask. The mask turned him into a red dragon when he was wearing. It worked well, and he used it for many years. Then one day it was gone, and so was his firstborn son. The servants told him that a red dragon had flown from the house. The merchant grieved the loss of the mask, and berated himself that he had not thought of a fitting sacrifice himself.
Currently the mask apparently hangs in the Tyche temple in Kangrisorn.
Game effects: When worn, the mask turn the wearer into a red dragon. The wearer is able to breathe fire and attack (claw/claw/bite) as a dragon. Later, he is able to fly. His senses are keener and he can smell precious metal. He is protected by scales, but can only use items that a dragon could use.
Phase One. 1 point for using the mask for the first time. 1 point for wearing the mask for an hour or more/or using the attack routine. 1 point for breathing fire. When wearing the mask, he is turned into a fire drake, a clumsy bloated lizard 8 feet long that cannot fly. He has an AC of 5 and does 1-2/1-2/1-4 damage. The breath weapon is a flame jet 4 feet long that does (character level)d6 damage. The breath weapon can only be used once per day. He can talk dragon.
Phase Two. Now the dragon is about 12 feet, the wings are longer, allowing the character to take off for small 'jumps' (25 feet), and glide from heights. The AC is 3 and he can do 1-4/1-4/1-8 damage. The breath weapon is a cone 6 feet long doing (character level)d6 damage. The character is protected from fire as if wearing a ring of fire resistance.The dragon senses should allow the character to find a few valuable coins hidden in a crack. Wearing the mask in negotiations makes the character almost impossible to cheat. When not wearing the mask the owner constantly feels as if he would be smarter with the mask on. Points as above and 1 point for using the mask in negotiations. 1 point for keeping 'sniffed' coins for himself.
Phase Three. The 'dragon' now extends to 15 feet, and fully airborne. The AC is 0 and he can do 1-8/1-8/3-24 damage. The breath weapon can be used twice per day and extends 30 feet doing (character level)d8 damage. The 'dragon' is immune to fire. When not wearing the mask the character will feel cold, stupid and weak. Indeed, the character suffers -1 to strength and intelligence each day until he has used the mask (accumulating at least 1 point) that day. If he stops wearing the mask, the loss is permanent.
Phase Four. For most purposes, the character is now an adult red dragon. His first priority is to find a cave in a distant mountain and make himself a proper lair.

Godstones (minor amulets). These are minor magical treasures usually in the form of a pendant, but they could appear as any small jewelry. It should count as a 'slot' considered the number of amulets one person could wear, but the same person could not use two godstones.
Eye of Ares: If the wearer rolls a 1 on a damage die, it becomes a 2.
Die of Tyche: The wearer may reroll one failed saving throw (once).
Quicksilver of Hermes: Gives a -1 to initiative in the first (only) round of a combat.
Belt of Thor: Reduces the damage from lightning by d6 (before saving).
Firestone (of Agni): Reduces the damage from fire by d6 (before saving).
Amber of Idun: Gives the wearer one extra hit point.
Opal of Anshar: The wearer gets accustomed to the dark instantly. +2 vs. light spells
Fingertip of Kali: The wearer is able to move silently for one round (once/day)
Silver of Diancecht: The wearer ignores exertion in regards to healing.
Eye of Heimdal: If on watch (only), the wearer may reroll any surprise.
Gem of Inanna: Cures infertility within one year.
Heart of Vahuan: Makes all who can understand stop and listen for one round (1/day)

Grimslade. Also known as "the Wizardsbane", this longsword +3 enables the wielder to surround himself with an anti-magic shell with a duration of 10 rounds once per week. It also detects magic twice per day. The +3 is disregarded, as is any magical bonus, when the anti-magic shell is in effect, but this is a minor distraction when wielded by the immensely strong Baron Arno, who received it as a reward after fulfilling a quest in Haskeem (see Al-Kuin).

Havoc (two-handed sword). This sword may simply be used as a two-handed sword +3, but if the wielder cries "HAVOC!", he goes berserk. When berserk, he rolls only a to-hit die (d20) and d6. If he hits, he multiplies his unmodified roll on d20 by a factor depending on the roll on d6 and the size of the opponent:

When berserk he cannot withdraw from combat or change weapon, unless he spends one full round attempting a Wisdom Check and succeeds it. If he succeeds, he may drop Havoc (he may not sheathe it). If he later picks the sword up again, he is punished for his cowardice by losing d20 hit points. Assuming he survives this, he is free to continue to use it.

Oil of Agility. Temporarily raises the Dexterity of the character to 18. Lasts 50-80 rounds.

Potion of Defense. Temporarily reduces the AC of the imbiber. Use the following table:

The effect lasts for 5-30 rounds.

Potion of Iron Constitution. This potent drink temporarily raises the character's Constitution by 6 or to a minimum of 20, whichever is greater. It lasts a number of hours equal to the character's Constitution (before drinking).

Reaver (scimitar). Reaver is a scimitar +0. Reaver ignores all metal or magic armor, but is deflected by 'natural' armor such as leather or quickness. This means that any metal armor (magic or not) is considered AC 8 as only the leather lining protects the opponent. Shields give -1 to AC because of the wooden parts. The ACs of monsters are generally not affected unless obvious (such as the case of a death knight). Reaver can hit any opponent that has no magic resistance.

Rings of Alliance. These two rings allows two different wearers to teleport without error to one another. The two wearers must touch the rings together after putting them on. This allows either wearer to teleport to the other. If either ring is taken off, the contact is broken. This could also happen if a ring is submitted to some kind of dispelling magic (the rings function at 12th level). The teleporting ability can only be used once per day. Either wearer will know if the contact is broken, but will have no idea of the well-being of the other.
If the rings are worn but not used for a month or more, the rings gain the additional ability to summon the other. The other can then teleport or ignore the call. Another month must pass before the summoning ability is restored.

Ring of Spell Healing. This ring is akin to a magestar as it absorbs the power of spells turning it into healing energy. Normally these rings are created with about 40 charges. When a spell is cast at the person wearing the ring, the wearer may attempt a saving throw vs. spells. If successful, the spell has no effect, but the wearer is instead healed by a number of hit points equal to the level of the spell. Thus a lightning bolt may heal the wearer three points. Healing above the hp maximum is ignored. The ring expends a number of charges equal to the level of the spell when absorbing energy. The effect is personal, so even though the wearer is not affected by a fireball, his companions probably will. Even if a spell would bring the charges of the ring below zero, it works normally for that particular spell. Once the number of charges is zero or less, it loses all magic if removed. But if kept on, the ring may continue to function. At this stage, however, the wearer loses a number of hit points equal to the spell level. The ring loses its magic once its charges becomes less than 10 below zero. Note that if the wearer fails his saving throw for the absorption, he is entitled to a "normal" save if applicable.

Ring of Double Action. This ring makes the wearer act as if affected by a speed spell. If the wearer is a spell caster, he may cast a spell and then attack (or something else). The ring can be used twice per day without any aging. In an emergency, the ring can be used a third time for triple action, but this makes the ring lose its magic (there is still a maximum of one spell per round).

Spellcleaver. This magic item appear to be a short sword, and may be used as such. But the real purpose of the 'sword' is spell defense. It is used akin to a sword of dancing, as the wielder uses one round to activate it (he is not protected that round). Then the sword dances for three rounds in front of the owner. He can then 'recharge' it (by spending one round). If he does this in the third round he is protected all the time, otherwise he starts over.
The protection is determined by rolling d6 each round:

The damage from spell is reduced by the factor after calculating the damage disregarding the sword. The bonuses only apply if the spell causes no damage in hit points (say a feeblemind spell). If the DM rules so, the sword may allow a saving throw against spells that normally have no save. If so, a saving throw of 21 is used, and only the sword's bonus apply to this roll.
The sword owner must be proficient with the sword short or suffer the to-hit penalty for not being proficient on the d6 roll.

Tutor (long sword).  A longsword with +2 on damage and able to hit monsters requiring +2 weapons to hit. The sword gives the wielder an effective level equal to the mean (round up) of the wielder's current level and 9. This boosts all characters under 9th level and may give them additional attacks per round.