I have seen quite a few variations that play four Zetalpa, Primal Dawn and zero Chromanticore, but the truth of the matter is that your deck only has a handful of spells that actually matter
Dubbed Sing for Me, this lets you play Ursula and exert one of your opponents characters
Blaster is a little more expensive at 5-mana, and he cares all about artifact creatures and Modular, which is a powerful mechanic, especially thanks to green with a card like Hardened Scales
The static ability of draining life can add up if you keep thieving creatures, but in most cases stealing that much stuff will cause you to win the game anyway its a bit of an odd design all-around, seemingly balanced for a more casual table but also sporting the option to permanently capture enemy Commanders
I dont think Id run this as my commander, though
Shell play any deck with either massive creatures or five-color shenanigans, but both is even better