rarity collection ii booster box YuGiOh 25th Anniversary Price Guide | Yu-Gi-Oh RA02 Ultra rare 25th Anniversary Rarity Collection 2:

You could certainly play the two of them as partner commanders instead of having Gavi lead the deck

You will receive 3-PACKS of Heat Wave Arena (JP SV9A)

Umbra armor's effect is applied no matter why the enchanted creature would be destroyed: because it's been dealt lethal damage, or because it's being affected by an effect that says to "destroy" it (such as Breathe Your Last)

The contingency of opponents having less life in the player youre attacking can get in the way, but if the game circumstances create a valid trigger, this black enchantment gives your commander deathtouch and indestructible until end of turn