He can also choose himself when you just need that 1 damage to survive a turn
Lets start by going over some of the Yu-Gi-Oh basics
You want to play the right type of Pokmon against your opponents types to get a type advantage and do double or triple the amount of damage your Pokmon would normally do. Trainer cards (including Supporter, Stadium, and Item) are cards you can draw from your deck to gain an advantage
While this may look like the art for Strength of Will, its actually a comic, not an MTG card
Granting Haste is a nice touch, but Firion, once again, requires a lot of resources for this particular line of text to generate value
Alliances does introduce cards that have an alternate cost to casting it -- exiling cards instead of mana