8/25/2017 Crimson Honor Guard¡¯s last ability triggers at the beginning of each player¡¯s end step whether that player controls a commander or not. Whether that player controls a commander is checked only as the ability resolves.

8/25/2017 Crimson Honor Guard will deal 4 damage to you, too, if you don¡¯t control a commander.

8/25/2017 The player could control any player¡¯s commander to satisfy Crimson Honor Guard¡¯s ability. If a player gains control of another player¡¯s commander ¡°until end of turn,¡± the player who gained control of it will still control that commander during the end step.