Kelsien, the Plague
Legendary Creature — Human Assassin
Vigilance, haste
Kelsien, the Plague gets +1/+1 for each experience counter you have.
: Kelsien deals 1 damage to target creature you don't control. When that creature dies this turn, you get an experience counter.
"Aim for an eye. Better they never see you."
Illustrated by
Commander 2020#11MythicEnglishLegality
Rulings
Each time Kelsien’s last ability resolves, it creates a separate delayed triggered ability. If you untap Kelsien and activate its last ability multiple times in one turn, they’ll each trigger when the appropriate creature or creatures die.
If the target of Kelsien’s last ability dies before the ability resolves, you won’t get an experience counter.
If a player’s commander would die and that player spares it by sending it to the command zone instead, Kelsien’s delayed triggered ability won’t trigger.
If Kelsien leaves the battlefield, you keep any experience counters you’ve received.