Whenever Agrus Kos becomes the target of an ability that targets only it, you may pay . If you do, copy that ability for each other creature you control that ability could target. Each copy targets a different one of those creatures. ( can be paid with either or .)
Cast Agrus Kos and build a creature-heavy board, then aim single-target activated and triggered abilities at him so he copies them across your entire team. You turn one pump, blink, untap, or counter-adding effect into a board-wide blowout, then swing with vigilance for lethal commander damage or a wide alpha strike.
Converts cheap single-target abilities into army-wide effects for huge mana efficiency
Vigilance lets him attack and still defend or trigger abilities
Punishes opponents who target him with removal-adjacent abilities
Strong in go-wide boards where copying buffs/counters scales explosively
Heavily commander-dependent; the engine stalls if Agrus Kos is removed
Needs the right ability suite—random RW removal does little
Vulnerable to board wipes that erase the creatures the copies pump
Abilities that target multiple things or aren't single-target don't trigger him
Wide token producers give Agrus many copy targets for game-ending swings.
Lean into cheap, repeatable single-target effects (Cloudshift, Ephemerate, equip-based swords, +1/+1 counter granters) so every cast scales to your full board. Add token doublers and reliable token engines to maximize copy targets, plus commander protection like Heroic Intervention and recursion to survive wipes. Trim generic RW removal that doesn't synergize with the copy ability.
Legendary Creature — Spirit Soldier
. If you do, copy that ability for each other creature you control that ability could target. Each copy targets a different one of those creatures. (