(2) Once per turn, when your opponent activates a card or effect that targets an Advanced Crystal Beast card(s) and/or Advanced Dark you control (Quick Effect): You can negate the activation
In conclusion, while I'm a bit skeptical about its potential as a commander, there might be space for a small reanimator build, perhaps lead by CelesCeles and centered around bringing back low-mana value creatures also thanks to cards like Return TriumphantReturn Triumphant
If your Dialga G takes a lot of damage, use Warp Energy to switch it to the Bench and promote Garchomp C (C) Lv.X to activate Healing Breath ()
[1] If this card is Normal or Special Summoned: You can Special Summon 1 Level 5 or lower "Earthbound" monster from your hand or Deck, except "Earthbound Prisoner Grand Keeper", also you cannot Special Summon monsters from the Extra Deck for the rest of the turn, except Fusion and Synchro monsters
My opponent temporarily has 3 cards in their security stack, then it becomes 2 cards
Monster Effect: When this card is Special Summoned, place 2 Aurora Counters on it