Attuned Epic Items
When a person performs some particularly amazing deed, it creates a sort of energy. In some cases, an item can absorb this energy and become more powerful. For example, a knight who single-handedly slays a red dragon in its lair may find him/herself with a fiery weapon. A bard who woos a goddess with his songs may find his mandolin is now a Canaith mandolin. However, when an item is enchanted in this way, the enchantment is attuned to the person who performed the deed. If a person receives an attuned item (you can detect attunement with Analyze Dweomer, not Identify), he or she must perform a deed of equal or greater awesomeness to reattune it to him/herself. In some cases, the new deed creates an additional effect.
In game mechanics, this means that at the DM’s discretion, an item of Masterwork quality or greater may be enchanted by an epic deed. This has nothing to do with alignment, but alignment may factor into the enchantment (as in axiomatic, anarchic, holy, or unholy).
In order to attune an item, the DM must roll an Attunement check, with the DC based on the awesomeness of the epic deed. More awesome deeds have a greater chance of attuning an item than less awesome deeds.