Not especially. For as early as you can encounter Marcus in act 2 it's pretty high though. I usually save his fight for right before I head to grab Dame Aylin and have gotten a bit more powered up.
After more thought on the matter though I bet OP has karmic dice on. That option being on can make those crazy long bad and good luck streaks happen.
My least favorite fight in the game. On my last honor mode run, Isobel started her turn by triggering Attacks of Opportunity from both Marcus and one of the undead. The second one paralyzed her, of course. She's lucky I happened to have a cleric in that party that could Sanctuary right after, otherwise she would have been gone.
One time in a tabletop DND game, the party wiped over bad rolls. It was partly my fault for over tuning the fight, but also bad luck. The party had a potion that was like "you can make an extra full attack this turn, all your hits do an extra 1d10, and you're hasted. Afterwards, you are paralyzed for 1d4+1 turns".
Fighter drinks it and proceeded to miss like 6 attacks in a row. I think he needed to roll above like 13 and just couldn't do it.
This is also why I prefer games that give players more tools to tell the dice to fuck off, like fate points in Fate or willpower in CofD.