Despite being rated difficulty 2, Infinitor is more than kind of a pain to play against. He’ll spam manifestations, many of which have their own unique challenges — Twisted Miscreation will only take one damage per hit, no matter how many bonuses you pile up –enjoy constant damage reduction, and do an end run around typical villain deck management techniques, because so much of his deck involves putting yet more cards into play.
So I put off unlocking Infinitor’s variant, Tormented Ally — or “Heroic Infinitor,” as he is more popularly known — because I thought it would be a pain. In fact, it only took two tries, in part because I lucked out with Dark Visionary almost always being able to put a manifestation on top, rather than one of his spammy one-shots.
The trick to unlocking Heroic Infinitor is getting a construct to deal the final points of damage. The two main options are Autonomous Blade and Wounding Buffer. Wounding Buffer is tricky because it needs to take enough damage to trigger without being knocked out of play completely. By the end of the game, compulsory damage bonuses can be high enough to take out a 4 HP target immediately. Autonomous Blade on Ra is how I wound up going. Once Infinitor was low enough, Ra did the penultimate wound and Autonomous Blade finished it off.
 Now I’m caught up on character variant achievements, for now.