02:09:59 PM Jan 27th 2012
FYI, in InuYasha this trope is first introduced during the fight with the Thunder Brothers (Hiten and Manten). After InuYasha kills Manten, Hiten eats Manten's heart to absorb his power, hoping to avenge Manten with their combined powers. The anime fudged this a bit to avert the actual cannibalism. Tessaiga can absorb the power (not just aura) of a strong yokai that it has defeated/slain, this extends to yoki weapons that have intrinsic power.
11:58:55 PM Mar 9th 2011
Please note that this trope is not limited to comic books or villains (granted that would make for a pretty strange hero). — GSC