(I was lvl 13 for this fight) For me, Laiken/Razakel were a joke compared to Amdusias; I'd still be stuck on him if it weren't for share dumb luck. The way I won, after several failed attempts, was that his arrows were hitting the ghost NPC that was in that room and not ever reaching me, so I was able to just land constant shots of my own arrows on him and eventually got em down. Of course tho, I would never suggest this a strat, simply cause it relies too much on luck, but I think the people out there that can't seem to win against him, should be aware of this
possible tactic.
(I was lvl 19 for this fight) As for my fight w/ Laiken/Razakel, I relied heavily on Charm (lvl 2)/Exploding Arrows (lvl 1/bow used: Disrupting Balanced Heavy Elven Bow of the Snake) to get me through it, and I had Sassan set to summoner style. It was pretty much an absolute fail on Laiken/Razakel's end

. What happened was once I charmed one of his own creatures, all the other Creatures, Razakel, and Laiken, went after that charmed Creature and I was able to spam Exploding Arrows for a constant ~200 damage and 300~ crit hits on Razakel

and also damaging the other Creature's that were near him(I focused on Razakel because when I drew hate, he was never able to damage me, unlike Laiken who could get hits on me pretty much anywhere). I didn't have to use many health pots either, just the occasional one to heal myself if Laiken started to spam his magic on me, but he always went back to the enemies I had charmed. The same goes for mana pots; just the occasional one when I couldn't support my Exploding Arrow spam. And I know it doesn't make much of a difference, since I've heard people have hard times even on the lowest difficulty setting, but my setting is on High. So, hopefully this will give people ideas for new strats for this fight

. Good luck if you're still on this fight! And hopefully this gave you a new way to approach the fight.