War Machine - Expert Ronan + Infinity Gauntlet

Expert Ronan is HARD, and without proper preparation, he can easily kill you in just 1-2 hits, with the starting stage 2 villain hitting you at a base of 5 damage (With infinity gauntlet and universal weapon) + 2 boosts if you're holding the power stone. Later on, when he draws fanaticism, even allies are only going to be of limited help when he's overkilling them by 6-7 damage.

He's no slouch when it comes to scheming either, a single scheme with boosts can easily push you over the first threat limit of 7 from nothing, so try to make sure you have Under Surveillance out or that he's confused when you flip to alter ego.

The answer? A healthy amount of stun, confuse, and using allies + tough statuses to survive fanaticism hits (piercing will remove the tough status on allies if you block with them, allowing your tough to soak up the overkill damage).

The first priority is to start setting up helicarrier/quincarrier + 1 ally on turn 1 asap, preferably using One Way or Another to pull out the side scheme that makes Ronan steal away the Power Stone. His boost EV is so high that you'd rather him have the stone than an extra boost card. Between using the Milano to cancel activations and the resources spent not losing - you're going to be card starved and will need all the extra economy you can get.

From then on it's a game of survival until you can set yourself up safely. Prioritize using the Milano to cancel activations to prevent infinity gauntlet triggers (and to just not die), and to thwart the various schemes for 3. You're likely going to have to survive at least one solid hit without dying, and you will likely have to rec multiple times over the course of the game (especially at stage 3 once he gets retaliate), making downtime and endurance pretty essential later on.

In terms of tech upgrades to prioritize - focus on getting shoulder cannon out early to deal with minions, followed by sonic rifle and upgraded chassis. Gauntlet Guns and the missile launcher are nice to have, but you're unlikely to have a lot of resources to spend to get them out for quite a while since you're constantly spending resources to handle threat and to just not die to Ronan's attacks.

In my successful playthrough (attempt #10) I went through 6 confuse, 3 stuns, 4 toughs, 7 ally blocks, and 4 recs.

Sometimes he just swings 3 times in a turn with fanaticism and you die, sometimes you just let one attack through and you die. Sometimes he just does tiny amounts of direct damage and you just die. Sometimes a single scheme generates 11 threat and you just die. Either way, Ronan was a beast.

Some cards that have niche uses that can be swapped out against other villains:

Target Acquired - Ronan has some nasty boost effects - you can swap this out for counterintelligence if you want.

Down Time/Endurance - Can be swapped out for extra thwarting events (Lay down the Law or Multitasking) if you don't need extra healing.