142.3. Units can have damage marked on them.
142.3.a. When spells, abilities, or other game effects deal damage, Units mark that damage on them temporarily. This can be tracked with coins, dice, or other markers, or by memory.
142.3.b. Damage is Healed from Units at two specific times:
142.3.b.1. At the end of each player's turn.
142.3.b.2. During a Combat Cleanup. See_rule_REF_444.1_DOT for more information about Combat Cleanups.