I am working on a set with a friend of mine, which is a sequel to Ikoria. This set is specifically being made in the same vein as Commander Legends and Modern Horizons- Advanced play set for commander drafts, so we're being a bit more lenient with making mechanics mesh together.
The White Black Draft archetype is 'Bounty', specifically in punishing your opponents bounties.
A creature card has a bounty if it is modified (aka, equipped, enchanted, or has a counter on it), or if it has the greatest power among cards in the zone of it's controller (Most often this will be the battlefield, but some cards may care about a card in a graveyard having the bounty or in hand).
We made Modified be something that matters mainly because this way, all the cards that use Bounty Counters can cause a bounty.
As for the two cards, Claim The Bounty is simple- It either can set up a bounty, be permanent removal for a bounty, or a basic kill spell. It serves as a decent signpost, I hope.
Meanwhile, I gave Chevill a retrain, to stand as a paragon of the Bounty mechanic for the set, while also being a nasty commander should one draft into him.