The other five cards are the reprinted enemy-colored Horizon lands that were first printed in Modern Horizons
Once you start attacking with this card as a 4/4 or larger with double strike regularly, youre in business
On the flipside, you could build a Y'shtola deck that doesn't focus on this Creature package at all, and you can win the game through alternate conditions, whether that's by dealing enough damage with Y'shtola herself or casting cards like Sheoldred, the Apocalypse, Bloodchief Ascension, or a personal pet card, Approach of the Second Sun
13 Skithiryx, The Blight Dragon Infect Your Opponents If youre looking to lose all your friends in the most efficient way possible, by winning a game of Commander via poison damage, then Skithiryx may just be the best commander for you