Rearguard when left alone either starting or allies die, continues using her ally protection skill and virtually casting it in the air losing a turn. 

If she does not do the stupidest thing ever she will be super strong alone vs waves and also for farming campaigns. She is basically bugged, she should not cast a spell that requires allies and does not do anything on her. 

Probably there are players who will be able to use her more and is their one of few epics. Regardless it is a bug need fixing.

Thanks.