For example, if one player has 10 life and the other has 17 life, the first player gains 7 life and the other one loses 7 life
But more importantly, if your opponent allows you to untap with a Hullbreaker Horror , it'll soon sink their spirit as well as their ships
Companions have been nerfed with todays new banned and restricted announcement Companions, introduced in the latest Ikoria: Lair of Behemoths set, were a way to play with commanders without playing in the Commander format
Also, cards that get a card from outside of the game (Living Wish, Cunning Wish, Research // Development, etc) are also not allowed
I wouldnt focus too much on this aspect of the deck, and I might even consider starting with the artifact-themed cards as cuts for potential upgrades
2 foil Legendary cards