Mr Dragon himself is a low-cost card that builds up when youre bringing in dragon-type creatures
This means you could exert a character with Ink cost two, a character with Ink cost three, and a character with Ink Cost five to play the card instead of using your own Ink supply
Whether that's untapping, having infinite ETBs, or something more complex, they all break parity in one way or another, sometimes through manipulation of the stack
Everyone save three people seated row four and forward died
The color limit also cuts down significantly on the possible decks that can be built, making it less overwhelming than a game like Magic that lets you mix and match with fewer limitations
For three mana, you get a Red 3/2 with first strike