Martell Lose to Win

Win by losing. Lose every battle but win the war in the end.

Joust

Use House of Dreams to start with Norvos, which, since it cannot be attached already becomes impossible for your opponent to remove or negate. This will severely limit the opponent's ability to beat you at intrigue challenges in the early game. In the late game, you should have House Dayne Reserves to insulate you. With plenty of influence it should be no trouble to return it to your hand whenever you need to then discard back into play as much as you want to protect your hand. That settles intrigue challenges, then for power challenges simply have no power to lose (at least early on). Combat challenges are the most difficult to insulate against. That is what Obella Sand, Moqorro and Maester Aemon are for. Moqorro and Aemon can be claimed for all your combat loses and then save themselves infinitely. (Volantis can bring Moqorro's cost of 5 down to 4, but paying the full 5 is not hard for this deck so do not worry about using an agenda to bring his cost down). Even still, they can only kneel once per round so I suggest not playing them early, best to have a backup copy equipped for further protection. As for Obella, simply keep duplicates in shadows and swap them around from shadows to dead pile and back again. This does mean you will need to play each one individually (which you will not be able to do until the first one dies etc.).

That settles losing challenges but what about dominance? An opponent does not need to attack to win, they can just have the bigger army. Do not fret, this is actually good for you. You need the opponent to have a bit of power for you to steal later. That's how this deck works. Nothing bad can happen to you because losing is part of the plan. Once your opponent gets a bit of power from dominance, you can steal it by turning power challenge losses around with Red Vengeance and potentially reset the opponent's board with Someone Always Tells. Winter Festival is a good way to bait an opponent into beating you at a power challenge so you can steal their power this way. And with the restricted card The Prince's Plan, you will never run out of Red Vengeance. You can also clear away a big board with Valar Morghulis (units can be saved, so Aemon and Moqorro should be fine). This is also great for clearing away a bunch of renown units.

Now for the win conditions. The main way you get enough power to win is by losing defense challenges. Put Taste For Blood on Moqorro or Maester Aemon (with duplicates to keep them safe), Moqorro is slightly better since he can protect himself against being discarded from play as well as death. That will generate 1 power per loss. Dorea Sand can also accumulate power by killing Obella's though there is only one of her since it is hard to get Obella killed on purpose when the opponent gets wise to not attacking you and the deck has no way to protect her. Ellaria Sand is also a good way to gain power. Use her to steal power from renown units or special attachments/locations your opponent tries to hide power on. Just keep in mind that the only way to protect her is with duplicates, so don't play her right before a Valar Morghulis. Quentyn Martell is great for getting power on your house, just don't protect him with duplicates, because you want all three copies to die separately. And save up multiple An Opening Gambits to trigger in one move for a surprise victory. There is only one The Long Plan because you can only trigger one per round anyways and it is surprisingly hard to trigger. Between Winter Festival, maybe 2 power reversals with Red Vengeance and a few Quentyns, it only takes a few losses with Ellaria or Taste For Blood to get the power necessary to win the game.

The other cards in the deck punish the opponent for winning challenges. Aero Hotah gives you spot removal anytime the opponent attacks with more than 4 strength, Outthought and Sun Stroke prevent the opponent from attacking more than once with units. Don't forget you can intentionally lose more than once with Sun Stroke to kill units with more than 4 strength.

And that's it. This deck is very frustrating to go against. It likes to lose challenges and can punish you opponent for winning, but also punish them for losing. It's a lose lose for your opponent.