So the set up is: battlemage character (HA, 2h, plus array of spells) somewhere over lvl20. The temple itself was easy - huge crowds of shades but they got 1shot with sunfire rarely even getting close enough to force me to get physical and I had heavy armour so I could shrug off their ranged attacks - once I had to summon skeletal wizard (with firecloak) to fish them out from cover and set up a lot of fire runes preemptively to blow up shades by the dozens. Overall a piece of cake.
Suddenly Malkoran. He had massive entourage of shades with him but that wasn't the problem (although they proved slightly harder than usual without good chokepoint). The problem was Malkoran's ranged health sucking spell that could off me in about a second (despite protective armor enchantment) and would top him off the moment I tried to send a summon against him (sucking that summon dry).
Ok, so plan the first:
Leave the followers outside. Pop all that could assist my stealth and ranged damage (not a sneak or an archer, mind you), get an ebony arrow (I had a small bunch saved for time of need like this) dip it in a powerful, slow acting poison, sneak close enough to get line of sight, shoot the fucker, run away if he survives initial hit, stay behind cover (anything else would feel unpleasantly like being drunk) and try to survive till he drops.
What went wrong:
Sneaking into range worked - barely. The guy got badly wounded, but survived, the poison started doing its nasty work and retreat was (barely) successful. However they guy had a healing spell, allowing him to outlast the poison by periodically healing himself. Also he topped off himself while I was running away like a sissy (nearly killing me), negating even the initial wound I inflicted. Still, the poison should prove some advantage.
Plan the second:
Summon storm atronach from scroll - surely it'll fry the fucker and zap his magicka away?
What went wrong:
Nope.
Plan the third:
Try to splash the guy with AoE spells while popamoling cheesily and trying to exploit pauses caused by him having to heal himself from poison's effects.
What went wrong:
Just nope.
Plan the fourth:
Panic.
What went wrong:
Still nope.
Plan the fifth:
Hide just by the doorway, summon something, then hope it will distract him for long enough for me to run at him like a retard (also letting him top his health off in the second or so it takes him to finish my summon).
What went wrong:
Surprisingly nothing. Massive armor-clad lizard guy turns to be able to knock a scrawny bathrobed fella over if he just runs into him at full speed, and that's what happened the moment he just about focused his health sucking efforts on me. Then it was just hacking desperately at the guy as he tried to get up.
...Then the guy came back as a shade and started firing powerful non-AOE fire staff and all hope was lost, but surprisingly I prevailed, despite spending most fight hiding behind pillar and screaming in terror as blazing projectiles roared by.
Net gain:
Neat staff, 2x Dawnbreaker (due to vanilla bug involving splash damage, also proof that scripting quests is evil) some misc loot, massive fuck yeah, a lot of FFFFUUU-n, can now use my balls as +5 flail.
I'm also more infuriated than ever by inability to disrupt stoneskinned casters by grappling or something in most games.