A factor that must be considered when building an Auto Duel Deck such as this is to make the Deck simple enough to be played properly by the A.I.
Fill your deck level-4 Warriors that will serve to make and power-up Zubaba General. For this example we used Noble Knights with swarming effects, but you can opt for other level-4 Warrior archetypes such as Gouki.
Dynatherium is easily put on the field without cost, helping you Xyz summon quicker.
Power of the Guardians is a steady source of ATK boost.
Fill the rest of your deck with draw effects to get your Xyz combo pieces sooner.
Utopia deals 5 times the damage to Shark. Slap some Power of the Guardians and some piercing onto it and you´re golden. If you haven´t obtained it yet from the Box, just use Yuma´s Skill to put a copy in your Extra deck.