Kallen should really be red. She's not a tsundere, which makes for something of a refreshing break from expectations, but she is an action girl, a rebel / freedom fighter, a warrior, and has quite a fierce temper.

I can't quite bring myself to give her the class type Warrior though. She's too good at working within an army to not get type Soldier.

I'm thinking that Kallen will be one of the few humans to have base power and toughness higher than 2/2. She is an exceptional athlete and fighter even when she's not piloting a Knightmare. She should be about 4/4: not quite as good as Suzaku Kururugi, but better than pretty much anyone else.

A saboteur effect would be really nice for Kallen, as that way when she's suited up in her Guren Mk-II she gets to do it twice. But it's not a big deal, as she'll also kill an opponent in 2 hits like that...

Unlike green and blue, the red rares in the skeleton don't include any card draw yet. So I gave Kallen a saboteur card draw ability with a red slant. Uncommon has several impulsive-draw effects (Rebel Spy, Ruthless Insurgent and Supply Raids - that's too many in fact, I need to remove one of those)... Anyway, my point is, I wanted a draw effect that wasn't an impulse-draw. I'm taking a cue from Subira, Tulzidi Caravanner here, and hoping that the preceding discard allows a red card to just straight-up draw more than it discarded.