Which level 7 creature is the best, and why?

Ancient Behemoths reduce defense by 80%, meaning an Archangel will have a defense of 6 against them. The Behemoth's attack is, I don't remember exactly, but it seems to be no more than 20, and its defense is also around that. Even so, the Archangel will still have higher damage, plus it gets the first turn. In my opinion, there's nothing stronger than an Archangel. And in terms of appearance, the Archdevil is probably the most impressive.

Added 2 minutes later
Although, it's not a given that the Archangel will defeat the Behemoth. But it will easily defeat any other creature. I also like the Titans.

Added 6 minutes later

2 Er@ser:
I just didn't understand the point. In general, I apologize for being so blunt...

And in general:
The Archangel already loses to the Behemoth even with attack/defense of 5. This, of course, doesn't put the Behemoth in first place, but it does mean something...

But the Archangel's damage seems to be higher by 40%, because 1 attack gives +4% damage (or 3, I don't remember, 1 defense gives -1.5% damage received, the maximum attack bonus is 400%, and the maximum defense bonus is -70%, so the Archangel needs 4 attacks to defeat a Behemoth with 0-0 stats for both heroes). The Behemoth's damage is unstable, and that's why it might lose. All of the above is just my personal opinion, as I haven't tested it in practice