Brimstone vs Ultron

Which villain?

Ultron, superior punching power and endurance, more intelligent, more dangerous and probably with much better feats and overall character development 😉

How does he have better endurance?

He is indestructible and cannot get tired.

I don't think Brimstone ever got tired. He's not even truly living. He's even fought inside the sun before.

Has he been hurted? I suppose he has no brain.

Ultron.