Help finding book.

I don’t remember a lot of this book but it was a harem and starts with a guy getting a class or something but winds up with a powerful women bonded into his core. I think she was a dryad it had something to do with nature faction.

He meets up with a mysterious black haired girl that uses darkness magic and then another girl he is with becomes a vampire. To get stronger faster the women in his core has them bath in a very painful liquid that makes them stronger to physical attacks. There are three different colors u use with each being more painful.

The main character has a spell where he shoots a seed and can explode. I first started reading it in 2021. Anyone know this story?