If the series goes on a while, have an entry set in the 20th or 21st century where some shady business guy digs up the slasher and tricks him into killing business rivals, only for the slasher to boomerang back and start violently tearing apart his company when the ruse is discovered.
Alk
Kevin Fox
Commentary: I Work Very Hard, And I Would Like To Try Cake
Last skeet brought to you by reading James Stokoe's Orphan and the Five Beasts and Stephen Grahm Jones' I Was a Teenage Slasher back to back.
Gacha player mentality
First 1/3rd of the sequel follows the normal schmuck who cares the slasher around in their cage, and then releases them if the slasher determines things are bad enough for righteous vengeance.
Hello. I am a horse. I work very hard at my job of being a horse. When humans say move the heavy thing, I move the heavy thing. When humans sit on top of me and pull on my head, I carry them where the...
It would be convenient if I had the "throws himself into exercise and/or work to avoid emotions" flavor of depression.
Like, I would still be depressed, but I would have less problems. Or at least different problems.
Considering how wuxia stories and kung-fu movies often love revenge, the genre seems like it would get on with slasher tropes like peanut butter and jelly.
For the sequel hook, have the wuxia-slasher locked away in a cage, with a "break glass in case of corrupt magistrate" deal: