Untap Endbringer during each other player's untap step. {T}: Endbringer deals 1 damage to any target. {C}, {T}: Target creature can't attack or block this turn. {C}{C}, {T}: Draw a card.
2016-01-22
Activating the second activated ability after a creature has legally been declared as an attacker or blocker won't change or undo that attack or block.
2016-01-22
Endbringer untaps at the same time as the active player's permanents. You can't choose to not untap it at that time.
2016-01-22
If an effect states that Endbringer doesn't untap during your untap step, that effect won't apply during another player's untap step.