That's what I took away from her story too, that she can influence people, make them give up on life, and then gains strength from their deaths. She doesn't seem like such a benevolent character after all when you read bits like that.
In the small amount that I have played her I have found No Prisoners is a good upgrade for her. She is pretty good at killing things, so can fairly reliably heal a little and then get the 2" push, which comes in handy for getting just out of range of models that your opponent had lined up to charge her. Being able to deal a bit more damage with the clockwork grenade bonus action helps this as well.