Creeping Death said:
What is the difference between artifacts, weapons of legacy, magic items, epic items, and relics? Can't epic items be made that rival or surpass artifacts or relics? Are their epic advancement rules for weapons of legacy?
Don't forget Item Familiars from
Unearthed Arcana also.
That said, artifacts are basically magic items that can't be created (by mortals, anyway). They can have powers beyond what's usually laid down for normal magic (or epic) items. Basically, an artifact can do whatever the DM wants, as they (for major artifacts) are the ultimate in magic contained in an item.
Weapons of legacy are magic items, but they aren't made with the various Craft feats. Rather, they're created by doing heroic (or otherwise incredible) deeds that imbue them with power. Anyone who finds an Item of Legacy can awaken its higher-order powers, but that requires a ritual investment (and a feat slot, maybe more than one) to do so. To the best of my knowledge, there aren't any epic advancements for weapons of legacy.
Magic items are standard items that are imbued with magic via a spellcaster with the proper Item Creation feat and spells. They tend to have limits on how powerful they can be.
Epic items are magic items made by epic spellcasters with the proper Epic Item Creation feat. They have markedly fewer limits on how powerful they can be.
Relics can be divided into two sub-categories. Ancestral relics are where you take a feat that allows you to imbue an item you own (that has been in your family for a while) and imbue it with magic power, essentially making it a magic item. Holy relics are similar to minor artifacts, in that they aren't created, but are items of powerful goodness. Both types are found in the
Book of Exalted Deeds.
Item familiars are where you can imbue an item with experience points and grant it powers and sentience as long as its with you.