Not only is Vivi a mana engine, providing free resources over the course of the game, but hes constantly powering himself up whenever his user is casting non-creature spells
First of all, as usual, lets peek into the rules thats always useful
Red: Deflecting Swat, Bolt Bend , Wylls Reversal , Wild Ricochet, etc
Fill any empty space with more packing material to ensure nothing moves around
This is also why the number of secret rares far outnumber the cards in the main set
To avoid spoilers, let's just say that there exist a number of scenarios which punish you for having certain enemies in the victory display, almost always having "Victory 0"