I was thinking that this Hero would be a tank that has a variant of Moiras drain. (Moira is too perfect a tie in for the character.) But it also increases it’s health to a cap while doing less damage.
Your max health would be added to the health of whoever you decided to fuse with. While fused you can drain or right click which makes a barrier like Brig on the direction you’re facing. (Doesn’t have to be the same direction your host is facing.)
Tons of ideas and a whole kit I have but can’t do the thread yet because I’m at work. Sound fun though doesn’t it?