Ring of Pain

Using this build I was able to complete this in 14:50 seconds.

Hermit Tiara - freeze
Misting Vessel - stealth skip high speed monsters
Polearm - attack on pass (you might get unlucky and die to a spike enemy but it is the only way to kill Owl fast)
Upgrade - scroll it really helps if you get this towards the end
Final form - scroll if you get it in room 15 save it and take it with you to Owl fight. (take care as it can be a bit unpredictable)

Stats priority
- speed to 21 asap
- attack
- health (mainly to tank accidental spike monsters hits with polearm)

Rooms and general strategy
- killed everything I could for the extra souls for rerolls and buffing up with the Upgrade scroll
- hunted stats boosts so I ignored rooms like the graveyard, shrines
- once you get to 20 speed you need to enter the Reprive room and kill Owl to reduce it's health by 25% in the final battle

Final battle
- scan the room and prioritise killing wall enemies
- when owl gets next to you just move back and forth and poke it with the polearm until 250 health
- priority number 1 is to avoid the beam attacks and kill the shrines
- once a shrine is down move towards owl. if he is too far you will still get in a few pokes with the back and forth technique from the first stage
- watch out for the chasing enemies so they don't reach you at the same time

You might need a few tries to get used to surviving the fight using the polearm and the freeze mechanic. Good luck!