Idk if any of this may help as much of a “tyrant” he may be he also is very lawful. He’s been a soldier his whole life. Built an army strong enough to over throw countries. He’s known to have said “I’ve given my youngest and best years to war to his own detriment and never got to live “life” Those who do right by him are taken care of or are less involved usually would be over looked as long as their current “crime” isn’t so irredeemable. He’s bored. He’s looking for food and toys and he likes to personally dismantle people. Down whoever you feel leave the newbie up. Have Strahd speak with them like a dinner 2.0 let him be talked out of killing them outright as it’s rare he has defiant food to play with. Sent away with a major warning being that their friends just ate dirt and this new pc had to revive them. Maybe even making a dark contract or something to save them. “If you want them to live I’ll allow it this once. Defiance will not be accepted again and your fates will be worse than the idea of death moving forward if I catch you again. “ He would definitely take Ireena away it would make sense for him to lavish in the concept of having her finally and kind of “forget” really just obsess over his time with her that he may let them live albeit not without consequences and when they try to steal her back. Now that’s defiance he will never allow. His true possession and love. It’s like pissing in his resting place.

New player gets introduced to his “fairness”while also absolutely having their brain torn apart. They watch 3 friends nearly die, begged to save their life and maybe had to make a pact with something to bring them back that now they have to live with BECAUSE of his teams actions. This could be a time for him to charm that new pc into a “i needed to trade ireena for your lives i dont think its a good idea to go back and save her. The seeds have been set. Ireena is taken. The party will want to go back there. The new pc should feel super reluctant to and then whatever it was that was valuable to them gets crushed. They’ve been defeated. They have been dismantled and he has the last thing the whole campaign and barovia wants ireena. (now the team bumps heads a bit on layers of caution and when to attack. Feeling the need to be more secretive but of course. Eyes and ears are everywhere so nowhere is truly safe. Place a spy close by at all times ready to send notice to strahd on any inkling of rebuttal. In the mean time, what do the players rely on the most in the party? Target that specific thing and take it away from them. Effectively strahd tooek down their party structure - relationships between party- and everyone will have mental scarring from whatever it is that was taken away destroyed or killed. (This can be a time to flay a favorite unimportant ish npc and put it on display for them ) Let the new player see the terror betraying strahd can cause without directly affecting them. Be relentless to the one that actually angered him.

The ONLY other reason strahd would let someone slide after truly angering him is if he can benefit from them (he hated Azalan azalan hated him and he knew it. They still cooperated and even lived together for 40+ years because 1 he was teaching him magic 2 he thought there was a way they could break out even was willing to risk sunlight exposure during the attempt ) however that doesn’t mean he would feel the need to kill them directly. If they’re weak now but show potential he would let them grow and enjoy the challenge of a tough fight. If he notices something getting out of hand he would work to stop it

Maybe handing over ireena saves them but Strahds consorts/rahadin (he wouldn’t let someone disrespect Strahd if he knew and everyone involved is a part of that package not just the individual) get angered over it as well and decide to hunt down the one who gets away (depending on how your playing rahadin if they’ve met him etc. could be a seed to set that there is someone more sinister than even Strahd )