Thrilling Encore and Command the Dreadhorde do have way too high CMC. Athreos and grave betrayed are a very good advice, I might get those cards for my Deck. What I do in my Deck is I play almost no additional pinger, instead I build around the you-cannot-attack-me cards in white, because Kelsien is really bad against Token Decks. Then I play cards that just really shut my opponents down like Sorin Markov, Overwhelming Splendor, Kulrath Knight, Kambal (Consul of Allocation), Stranglehold, Elrish Norn, Stigma Lasher (I can really recommend this in a Kelsien Deck), Kunoros (Hound of Atheros), The Immortal Sun, etc. Some of those might really increase the price though... I try to shut other peoples creatures down with Kelsien and cut off their other strategies they might have. This is a different theme that just serves as an alternative idea. The reason I chose this way is because I was looking at Kelsien, obviously I wanted to give him Deathtouch. But when he has deathtouch I didn't consider cards like Torbran to be that effective anymore so I tried to go into anotheer direction.
Grafted Exoskeleton + Chandra’s Ignition makes you needing less counters to win. Soul’s Fire and Gravitic Punch can also do this however to only one player at a time.
Primary win with kelsien: Commander damage Secondary win with kelsien: lock down the board with some urborg (all lands are swamps), and kormus bell (all swamps are 1/1s) Jank and watch everybody hate you for eternity
Very late response, but I believe it doesn’t. Kelsien isn’t what does the damage to the creature, Chandra’s Ignition does. It just scales off of Kelsien’s power.