Halo MTG set

I'm thinking of making a MTG set of Halo cards. I am wondering what specifics I'd need for each card. I plan on making everything balanced, as a lot of MTG fan cards are overpowered. Any thoughts on this would help. I'm already working on a Starcraft set, but that's kind of stalled due to lack of ideas at this time, so I wanna get a new idea pool brewing.

Well if you're working with characters from the Halo series I suggest making a card that generates disposable marine tokens as well as giving green and red to the UNSC, white and blue to the Covenant, and black to the flood. Perhaps giving foreunner strstructures and sentinels artifacts?

And of course giving the most prolific characters in the series legendary creature or planeswalker status.