Talk:Grimm/@comment-84.184.141.147-20150308150943/@comment-4010415-20150308193918

They can also be compared to the Heartless from Kingdom Hearts.

The Heartless, unlike humans and other living beings in the various worlds, don't have hearts. They're shadowy creatures that are driven by instinct to attack people and other completely sentient living beings. When defeated, their bodies disappear.

Though, the Heartless turn other people into Heartless by stealing their hearts, and when you kill them, the hearts they've stolen float away. It's really fun to see if you can spot a heart flying away when you kill one in Kingdom Hearts and Kingdom Hearts 2.