Ares is your best tank among all your reds. He will make your other heroes better but if you use him as a tank, then you don’t want to stack same color as tank, too easy for opponents to stack vs ares + whatever red you decide on.
So none of your listed reds will be on your defense.
Anzogh will have most synergy with your other red heroes. What other reds do you have maxed? BT, falcon, Scarlett?
You have the rings so you can always save 6 and ascend somebody now (my 2 cents). You have Ares so I vote for offense - either Azlar or Elena depending on what class you need to fill. I’m working on my Elena now (she got a decent buff in V20) but I wish I had Azlar so he gets my vote. That said, I’m very optimistic about using her counterattack for PVE in events so depends on how you want to use your hero.
I prefer Elena over Azlar. On high level titans, S2 hard, events, etc. she is amazing. That riposte punches back, hard. My Colen level 10 is shaping into a nice Azlar clone. I expect when he’s done it’ll be pretty close.