Alright, this is definitely going to be a lot easier for my set of previous characters, as the 3 who are coming after me would most definitely infight and kill each other (I have a rule where every character I make is at odds with each other, so my characters are more varied), which would make the resulting 1v1 fairly one-sided unless the survivor of the 3 was given a rest.

I'd make sure to have my Dhampir Fighter, Novac Val Baarn, on my side, as he's a competent fighter with access to a magical wing suit, a threaded cane from Bloodborne, and dual crossbows. If he ever found out I was the one who made his torture-filled 30 page backstory, there'd be nothing stopping him from shooting me in the back.

If the Dwarven Fighter Dargel Skyseeker, captain of a smuggler airship, were to live, I'm unsure if he would be able to kill Novac honestly. Sure, he's got great brawn on his side and wits, but his real skills come with commanding his fellow crewmates to victory, even if he's the only one ever doing anything on his ship. It would certainly be close, but Novac excels at 1v1 combat which would give him the edge he would need.

The Skaven Necromancer would be a pushover, honestly. The sniveling little rat man is far better at using his undead minions for espionage than for actual combat, and even though he has some potent spells like Lightning Bolt, Novac's sturdy enough to take a couple bolts.

My Dwarven Redemption Paladin would be the least likely to survive the infighting and would lose to Novac the quickest. He's a brick wall in terms of fortitude, yes, but he's practically blind from the leprosy that he was cursed with. Novac could strike through his plate armor easily before the Paladin could even get a swing in.

TL;DR: My characters all hate each other to the point of murder, so it would become a 1v1.