Ares' special power, Everyone Must Fight reads : At the end of each opposing player's turn, deal one penetrating damage to each character that player controls withing 4 square of Ares that didn't make an attack this turn.

The description for Support starts out: "Give this character a power action and make an attack roll...."

So could a character avoid taking the damage by using support to heal a friendly character?

No. Support is not an attack; it just uses the attack roll mechanic to make matters easier to explain.

Thanks.

It seemed like a cheesy way of getting around the power so I'm glad that's not the case.