I'm a stubborn old MM / SV Hunter who never liked BM -- never even touched it on my main Hunter -- and decided that I had to do the Fenryr challenge as MM. Being a father of two also means I am a lot more casual than I used to be, so I ended up having to tackle the challenge after 7.3 went live and Mythic dungeons had their difficulty increased to compensate for the current content and gear. While researching the challenge, I got the impression that Hunters were struggling to beat it on anything other than BM and, although I don't know that it'd be possible to do it as SV due to the kiting involved, I can confirm it's definitely doable as MM and I thought I'd share how I did it.
My character has an ilvl of 933, I used the Prydaz and Sephuz's Secret legendaries for some extra survivability and haste / run speed, and I used the following consumables:
- Defiled Augment Rune
Flask of the Seventh Demon
Nightborne Delicacy Platter
Drums of the Mountain (on both pulls)
Potion of Prolonged Power (on both pulls)
- Careful Aim (on the 1st pull) / Lone Wolf (on the 2nd pull)
Lock and Load
Posthaste
Patient Sniper
Camouflage
A Murder of Crows
Trick Shot
For the second pull, after he fled to his cave, I dismissed my pet and switched to Lone Wolf. This is where I think SV simply wouldn't work, because (I believe) you have to kite him to be successful. That's what I did -- I kited him around the lake, again saving my Disengages for Ravenous Leap, and using his casts of Unnerving Howl and Scent of Blood to gain distance, or pop off some well-timed Aimed Shots. In my experience the second pull was the easier one, probably due to Scent of Blood, which helps with the kiting. I ignored the adds he summoned -- they followed me but never really got close to me, and therefore weren't a threat.