I agree, that works much better than what I was thinking.
That said, I think I would lower the damage to something like a d4 and have it only apply to unarmed attacks, or attacks with natural weapons like bite, claw, etc. Maybe even allow a dex save to avoid the damage. That way it's not quite so overpowered.
If it went away as the engine upgraded, people might decide not to upgrade. There would have to be some incentive to upgrading her beyond resistance and Immunity to charm. Charm doesn't come up much anyway
I also agree with this. There should be some sort of incentive to upgrade her. For what it's worth, I have no idea what the whole charm stuff is about with her upgrade. What the heck does that have to do with her having an infernal engine upgrade?
The question is, how is the engine *supposed* to be helpful? What's the point of the engine? I know it's supposed to make her stronger in combat, but when it's working properly, she no longer burns those who get too close to her? That almost seems like the opposite of what the engine should be doing from Zariel's perspective.
I don't know. Maybe it should give her a fiery burst option.
Or maybe it should simply allow her to toggle the Warm Shield on/off, while at the same time allowing the damage to affect *all* melee attacks instead of just unarmed ones.
Just spitballing ideas here.