It could even be triggered by casting a spell - the spell would say "When you cast this spell, Discover X"
Whenever a creature you control with myriad attacks, for each opponent other than the defending player, you may create a token that is a copy of that creature to attack that opponent or a planeswalker that opponent controls
Kess is an incredibly flexible card that can helm a deck appropriate for casual strategies all the way up to cEDH brews that focus on powerful combo lines
Also, if youre playing partners or Choose a Background pairs as your commander, this can save a significant amount of commander tax later in the game
Ive played against it a couple of times in Brawl on MTG Arena, and if you cant deal with Narset before it attacks, it's pretty much game over due to its ability that lets it target non-creature spells from any graveyard, exile them, and cast a copy for free
Tajic works because he is cheap and has the most powerful ability for multiplayer: indestructible