A permanent is removed from combat if it leaves the battlefield, if its controller changes , if it phases out, if an effect specifically removes it from combat, if it's a planeswalker that's being attacked and stops being a planeswalker, or if it's an attacking or blocking creature that regenerates (see rule 701.12) or stops being a creature
Ignoble Hierarch A powerful mana dork Ignoble Hierarch is a one-mana Green 0/1 that you can tap for Black, Red or Green mana
Koma offers something different compared to other Simic Legendaries as it cares about interacting in combat, rather than unloading your hand with lands to draw more cards
8: Target player gets an emblem with "Whenever you activate an ability that isn't a mana ability, copy it
Commander owyn, Shieldmaiden First strike At the beginning of combat on your turn, if another Human entered the battlefield under your control this turn, create two 2/2 red Human Knight creature tokens with trample and haste