Ares does great damage at the expense of giving green AP with one ability and dealing damage to himself with another ability.
On defense, he could get down to 1 health and it wouldn’t matter. Sustainability isn’t a thing as a defensive character. So big damage is more important than the hits he takes back from giving green AP and for damaging himself.
Yes, they eventually take him down faster. But with 5880 health, he is hard to take down.
For that reason, you may want to take him out first before he gets rolling and starts throwing out 2k and 3k hits.
OBW, however, has two ticking time bomb abilities. If she farms enough for her blue, she just made most of what you did up to that point pointless.
And like self damaging abilities, the fact that her healing isn’t true healing has no bearing on defensive fights.
And her other ability can set you back literally 4 or 5 turns.
If you need 12 yellow to kill her, and she casts her purple the turn you got your 12th yellow, it may take you multiple turns to get another yellow match.
That gives Ares enough time to farm yellow or green or even red and deal massive damage to you.
And OBW heals and steals more.
There really is no winning strategy. The best case is usually taking out OBW before she accrues 9 blue or 9 purple, but without your own Ares or even a 3 star, that is a tall order. And if she does get her blue off, now you have a half health OBW and a full health Ares and they’ve had like 5 turns to build up for Ares to wreck you.
Let me put it this way:
I have 7 maxed 3 stars, a 245 Xforce and multiple other high leveled characters.
Ares still stings.