User blog comment:B214/Volume 17 spoilers./@comment-117.217.186.212-20140224111716/@comment-14716567-20140228205119

@Jopjopjop

When Vali Divides hes attacking them, with this absorb he gains increased power when they attack him. It's along the same lines but different.

@Emelas

I've never seen that series so I can't confirm, however another example would be the Dragon Slayers from Fairy Tale. They increase their own power by "eating" their respective element(fire, iron, etc).