There is no triggering of an ability, and the number of Poison Counters scale with the amount of damage the creature with Infect is doing
Tarrians SoulcleaverTarrians Soulcleaver, LashwritheLashwrithe, Blackblade ReforgedBlackblade Reforged, Wrecking Ball ArmWrecking Ball Arm, Thran Power SuitThran Power Suit, Cranial PlatingCranial Plating, and NettlecystNettlecyst beef up Kains power a significant amount and push him close to, if not well beyond commander damage range
Devilish Valet
It is not that Bird is so high on this list that is surprising, more so that there are four other cards between it an Noble Hierarch which is a very similar card and situationally better than the Birds
None of these issues were enough to ruin my experience, but it breaks the immersion when watching pack-opening animations stutter
This commander is a discard payoff, and its a nice combo with Sadistic Hypnotist since you can sacrifice the elf tokens to make them discard more cards and make more elf tokens