Braindead Solo Mark Of Honor Farm - Exalted Reputation Achievement

Location: Depths: Tower of Trial II

• Buff yourself to be able to one-shot one of the Executioner Type Losts on the first level (~12k HP) and use Night Fog Veil.
  
• Jump down and kill the right Executioner Type Lost.
  
• Use Mistle Root and repeat.

Don't bother killing the left Executioner Type Lost. He seems to have a different drop table.
On my farm runs I was averaging 53 marks per hour (173 repetitions per hour).

My setup is based on the Judgement’s Shadow (Hades) Build[fextralife.com].

You won't need to replicate the full build. I was already able to hit 14k+ charged strong attacks with this setup:

Blood Code: Hades
Weapon: Judgement Edge +10
Passive Gifts: Two-Handed Sword Mastery, Strength Up, Strength/Dexterity Up, Revenant's Greed (increases drop chance to ~30%)
Active Gifts: Night Fog Veil, Flashing Fang

If you are struggling to one-shot the enemy, check out the active gifts section of this build[fextralife.com]. The enemy also seems to be weak to blood damage, so the Blood Weapon active gift would also be a good option to buff your damage.