Ok my level 90, mage-warrier just got him doing combat also... 1 hand combat duel wielding with 2 dremora's helping. i cojnured 2 dremoras 1st ... went in fighting but no sneak hit & my first hit not a power hit to be fair... clicked the potions a lot to restore health and maintain full stamina to get in duel weld power attacks ... My armor is maxed, and my swords smith-ed to about 300 but i have no weapon enchantments.
None of my armor enchantments helped because they where mainly destruction, magic regen, conjuration, resist fire, shock & magic... also some carry enchantments, a minor regin stamina enchantment but works so slow really more useful for sprinting than combat .... wish a few enchant 1 hand & more health boost for him .... basically every time stamina dropped i drank potions and only refreshed health once with grand healin... mostly refreshed health about 3 times with potions ... the only way is to kill him for me is fast & stay up hill so he doesn't shout u over the cliff ... hope the dramora's get his shouts .... i was very short on health potions, i rarely use em and just not stocked .... i am 600 health with had 1 ultimate healing, about 2 vigorous healing potions and a about 300 health of minor health potions. usually i like to have over 10 ultimate healings then i stop hoarding em. lucky i had tons of stamina potions. My sword strength is still high (previous said i resto loop it)... but if more normal swords say the blades sword smith-ed to 150 and say a suck health enchantment ... maybe a paralysis but i bet he resist paralysis, maybe weakness to fire on sword poison (the dremora are hitting him with fire swords ). With LOTs of potions seems it could be done more easily. I repeated again to make sure not a fluke and easier the 2nd time but with out more ultimate healing potions id say he would win more than me maybe any minor mistake or bad luck and ur done for. my stamina is only 125 so more of that would help too. usually i just heal and my respite perk max's my stamina and time not so critical but once he stuns u he can take u down fast .... i cant recover from a shout with out more potions. seems strange he deals so much damage his swords only 39, he has two forty 1 hand 40% enchantments tho .. his vampire sword has a absorb 25 health for some amount of sec but i was takin a lot damage for my health so high (600). it was daytime so my stamina, magicka and health not regenerating since i am vampire but its fast fight so doubt that has much effect. well my magicka regins fast with all my enchantments but i just mainly healed with potions not left hand grand heal coz each duel weld power attack seems to stun him a frac of sec ... i still think he may reflect some in a random way, coz my health was droppin fast ...
Heavy Armor perk from skyrim usep:
Reflect Blows 10% chance to reflect melee damage back to the enemy while wearing all Heavy Armor: head, chest, hands, feet.
makes sense each hit say i put in 400 damage and 1 in 10, he reflects back 400.. that would drop my health fast .... i had to hit alot and fast ... so adds up.
along time back when i started playin master i changed my style ... each build i try to get something to kill fast if there is a bad boss and take em out first & fast ... if archers i take em out first out first, at master they put in lots of damage ... at adapt and expert u can kinda trade hits and blocks or just hit and reheal with magiaka till u wear em down .....at higher levels often they got bigger health/magicka researves so normal hits do so little damage, they heal all most as fast as your hurting em. ... my thoughts at higher levels its best to kill those attacking u with lots of damage fast i feel (or run if u cant ur out matched) ... ... but usually i like to have perks such that theres some one to take out the main bad guy quick.
i tried archery and stealth but could never get in 15x hit during combat. i am missing most of the archery perks just got the lower 5/5 perks. So i got him once as mage (destr - conjuration ) and once in combat (the dremora's helped distract him and took the shouts... in combat i won in less than a min, but i have so few potions thats the only way i could). more resist magic might help resist his vampire sword .... strange i am sure once he one killed me when it seemedi just filled my health ... so he may reflect ur attacks ... thats why i could only win gulping potions .... i went in potions and maxed my health (600) got out did a power attack and i died ... maybe i had residual shout affects ... he is tough. i don't really fight with a shield and it would be interesting if any one had any luck with shield or any luck sneaking around getting in 15x hit...