Instead of leaving the house, he merely expanded its walls until it consumed the entire world
To keep you in battle, use Shaymins Fragrant Flower Garden Ability to heal 10 damage from all of your Pokemon, and if needed, use the Irida card
Now onto the creatures, starting with Angelic Aberration, one of many payoff for keeping all your Scion and Spawn tokens around
The reason you pay the life is so that, unlike Terramorphic Expanse or Evolving Wilds, the land doesnt enter the battlefield tapped
Itll have to be a red or colorless dragon due to color identity, but you can get heavy hitters like Hellkite Tyrant or Ancient Copper Dragon, just to name a couple that benefit you when they deal damage
Losing the ability during the game doesnt cause either to cease to be your commander