the strongest, unupgraded unit at level 7.

It's too early to close the discussion. Not enough people have expressed their opinions yet. Just because you expressed yours, does that mean we can close it? Smart guy.

In my opinion, it's the Monster. The Angel and the Devil are very strong, but in my opinion, ignoring 50% (as far as I remember) of the armor is serious. Although, it might be a bit slow. Still, the Angel and the Devil will be more formidable, but overall, it's the Monster.