Board Thread:Questions and Answers/@comment-74.171.223.217-20130428171035/@comment-92.25.155.251-20130611193239

Yes they can. In Ben 10 Ultimate Alien, Verdona admits that Anodites CAN die if all their energy is drained. In Absolute Power Part 1, Ultimate Kevin was draining all of Gwen's energy and was actually killing (aside from being part human). If Kevin held onto Gwen longer while absorbing her she could have truly died.