Cryogen

Flying, Defender

When Cryogen enters the battlefield, place 5
time counters on it. At the beginning of your upkeep, remove one token from it. If Cryogen
has no time counters on it during the
beginning of your upkeep, exile it and create a
6/3 blue human wizard with first strike.

He yet lives?! I thought him slain by Calamitas. It appears she imprisoned the Archmage to spare his life. That frigid mass was an old construct of his, within which now he is imprisoned.