Mogh, Lord of Blood is a menace if you’re unprepared, but bringing a few items along and hitting the right level before you approach will save you a massive headache. Delve into Moghwyn Palace, take a deep breath, and get ready to spill some blood.
Mogh, like his brother, has a shackle hidden away that will briefly bind him to the ground. If you can make it all the way to the bottom of the Subterranean Shunning-Grounds beneath the capital city, you’ll be greeted by a pair of nasty lobsters. Sprint past them, ducking into the fallen pipe for cover, and you’ll find Mogh’s shackle in the far corner.
After claiming the shackle, we should make sure you have the Purifying Crystal Tear. This crystal tear will nullify most of the damage Mogh’s horrible, obnoxious (terrible, irritating) ritual will inflict on you. You may already have it if you’ve come across Eleonora, Violet Bloody Finger in the Second Church of Marika up on the Altus Plateau. If you haven’t, she won’t be a difficult fight if you’re truly strong enough to face Mogh.
With these two items in tow and a weapon that can inflict bleed damage (ironically, the Lord of Blood has a nasty bleed weakness), your fight won’t be a breeze, but you’re going to save yourself a ton of frustration. If you’re still having a hard time with Mogh, we suggest taking the time to claim Black Knife Tiche’s spirit ashes by defeating her mother in the Evergaol in southwestern Liurnia (this does, however, require making your way through Ranni’s extensive quest).
You might not want to take on this battle unless you’re around level 100 or so. Make sure your Wonderous Flask is equipped with the Purifying Crystal Tear and take a swig before you enter the arena — the effect won’t wear off until Mogh’s ritual triggers midway through the fight. When he approaches, apply his shackle liberally, you’ll be able to proc a hemorrhage two or three times before the shackle is rendered useless.
When his countdown reaches zero, he’ll plant his feet and start healing himself. Don’t let the healing deter you. Your purifying tear will protect you and give you the opportunity to rack up some free damage and apply another hemorrhage. The second phase is remarkably similar to the first, don’t let the flames on the floor send you into a panic. If you want some breathing room, you may want to rely on ranged attacks while you weave your way through the bloody magic napalm.
Good luck, this is a tough one, but we believe in you.