**Fast, happy DC Karlov and his pet cat** (Duel Commander)

Ok, it should go something like this:

1) Get a one drop out, like Soul Warden, Mother of Runes/Giver of Runes or a 1/1 beater with lifelink or even better: Authority of Consuls/Land Tax.
2) Play Karlov turn 2 and pump him up.
3) Tutor up Shadowspear to give Karlov lifelink and trample. And watch those nice +1/+1 counters pile up on the Fat Ghost Clerk.
4) Win through commander damage! Trample and lifelink FTW!

Back up plan: Equip Famished Paladin with Sorcerer's Wand and give it lifelink with Shadowspear/Spirit Link/Vampiric Link/Vault of the Archangel for infinite player damage.

About the deck:

Nothing extraordinary, just a speedy lifegain/control deck. Since Lurrus is the designated Companion every permanent cost CMC2 or less. This is the Achilles Heel since you drop your hand very fast and as such need to draw a lot of cards to not fall behind. It's very vulnerable to board wipes but can regroup relatively fast since Lurrus ability let's you play a permanent from your graveyard each turn.

With Karlov's triggered ability it's pretty easy to get him up to 20/20 if he's out a couple of turns. He'll be targeted with everything in the meta so he really needs to be protected from removal.