Thats the definition of Hullbreaker Horror, a card that can dominate entire battlefields when resolved, and it's often the mirror breaker of preference in control matches
The Decks main strength is its Rank 4 monsters, but it can also use monsters of different Ranks
As for upgrades, this ones fairly straightforward: 4x ST2 Tsunomon + 4x BT1 Upamon +1 DemiVeemon BT2 Replace all rookies that cost more than 2 with BT1 Elecmon and BT1 Gabumon Take out all Campion-level digimon bar Grizzlymon and replace them with BT1 Garurumon, BT1 Leomon, or an aggressive Champion you pull from later booster packs
Special Summon 1 Level 4 or lower "Crystal Beast" monster from your Deck, but negate its effects, and if you do, add 1 "Ultimate Crystal" monster from your Deck to your hand
The Growth of Creature Types Matter Over the course of the game's history, Creature types quickly accelerated in relevancy
its about holding a slice of Pokmon TCG history, back when promos were events in themselves