Notes & Combos
Going-second deck for OTK. Use your 5200 Atk Gaia fusion to swing twice for game.
Core cards are the Gaia cards + Shark Fortress + Book of Eclipse, the rest is useful filler. Feel free to substitute in Mystical Space Typhoon, Swords of Concealing Light / Book of Moon, or more of the one-of Gaia cards.
Shark Fortress is really good for OTK when they don't have two monsters to swing into and can be summoned if you have 1 Curse of Dragon (CoD) on the field and one in the hand (for fusion). Spiral Fusion the Lv5 CoD Fusion using the CoD in your hand, not the one on the field. That gives you two Lv5 to Xyz into Shark Fortress. Detach to let your Gaia fusion attack twice (even on an open board).