So I definitely like this faction, they're a pretty cool idea! But it feels a bit weirdly steam-rolly towards other factions. Like if you move a pack into an enemy clearing, the fact it automatically captures an enemy piece (or deals 3 damage to a Vagabond) just by moving there is a bit rough. Especially when they already come with 9 units on the board on both sides right out the gate.
Plus, I don't see where "vehemence" is tracked on the board.
Plus, what happens when a non-King's Gambit unit kills an enemy? Do they just not have a supply they go to, or does that person send them to their own captured units, or...? And if so, how do they get redeployed?
Lastly, both packs have separate hands? That's a bit rough to play around with.
Don't get me wrong, these criticisms aren't to shoot the idea down. I'm actually -extremely- interested in this idea, it sounds really cool to have a weird faction that you control one half per turn than one enemy faction gets to 'push' it along in a funky way, makes for a pretty crazy idea. I love that you even had an Advanced Set-up, that's pretty cool! I also might be mis-reading some parts, but yeah. Like I said, I really like the concept, I like the theme of how it's sacrificing pawns in chess, and I think it's really creative! :D Hope to hear some more on it!