What was your character build? How much is your corruption?
Can't subjugate Level 4 on normal difficulty
My "unarmed" run on Prisoner, since I still didn't have all the title passives that can help turn Karryn into nearly a god, was to make her a big masochistic slut who focused on raising Endurance. The annoying part about Level 4 on slut runs is that hall right before Noinim, and Noinim himself being kind of an asshole when it comes to sexing him up for the victory (you need to make him cum like 5 times and it takes forever to even get him erect). Having the passives that basically give Karryn the ability to heal Energy anytime her orifices receive Cum is a must, and Sight/Sex Resistance stuff helps too because there are points where she can wind up having repeated orgasms and you literally can't do anything.
Finally, I just kind of played a lot of it on auto-battle (Pleasure Stance) and let Karryn absorb a lot of "experience" until victory. I did get the sex skills so I could initiate some and pick battles instead of getting fingered to death early in some encounters.
Now that I beat it, I feel an actual sense of accomplishment because Prisoner mode with the Prison Fighter challenge is extremely stressful. So many times I wound up in fights I didn't want to be in cuz pixel collisions, and you can't run away so you HAVE to fight and win or suffer the gang-bang for losing. I still think combat builds are easier, save for Challenge runs.
EDIT: Oh nice, I got the achievement too
Prisoner mode requires too much grinding. After beating it, Warden mode feels like a safari.
Ain't that the fucking truth. I knew I was in a hellish wasteland the moment Karryn was receiving 47-90 pleasure damage for someone saying something dirty to her. I was like "COME ON, REALLY?!"
Karryn became such a huge masochist that even I was starting to insult her.