If you're 1v1 with a defiance-wielding paladin, you should probably just flee before the first full round of combat unless you're an extremely decked warrior that bashes well/a villager/shaman. Realistically, that's the fight the class is designed for, so it would be like fighting a invoker in quicksand, or fighting a whip spec in the village. The chance of you dying to some crazy RNG defiance luck is almost always higher than your chance of killing him.

If you have to defend, use forsaken portal if you are a scion to soften him up, I almost always leave and come back after he's been fighting for four ticks, so you have some chance to catch him slowed/softened (same with Empire inners). If I lose the item, I don't even bother to try and retrieve most of the time. Your best bet is to take their item while they are offline, and wait behind centurions or something (preferably with hiding classes and someone who can curse, and surprise them. The thing you have to remember is that Defiance + a full set of good equipment takes 10+ hours to accumulate, and without skyhigh saves and Defiance someone else wil eventually kill him, so if you can gang him once it's hard for him to get rolling again, since every random evil is going to take their shot at him now.

Best thing you can do vs a paladin is gear for saves, and use resist positive if you have access to it. A defiance wielding paladin with light of heaven vs a duergar warrior is probably one of the absolute worst matchups in the game, and I've managed to win the bad side of that a couple times 1v1. Probably my best advice is that if you are ever fighting an extremely powerful character, you should run the first 5-10 fights immediately, that way you can be sure they aren't prepping, then give it all you've got when he's not expecting it. Stacked double virtue tattooed defiance paladin is basically the good version of a lich, so treat it with respect,