This achievement unlocked for me after a full clear with all five Moura tears without using a continue, but not during my previous two full completions where I continued many times (10+).
I had not gotten all of the secrets that are required for individual achievements and for the Hero achievement, which I earned on a separate run.
I am not sure what the exact requirement for this achievement is but it's likely for a full game clear with all five Moura tears with either with no continues (which wouldn't make sense as that's what the Purist achievement requires) or with fewer than four continues since more than four results in the Martyr achievement.