Resolved Reincarnated as mid boss

A jp novel where the MC is transported to a game he played but he become a mid story boss. An Ogre/Oni I think. He guarded a tower of a mad wizard. He beat the wizard. Ventured. Met and rescued a vampire girl. The vampire girl call him Shutendouji. He's collecting jewels/gem I think.
Then he met the heroes of the story.
Then he met the secret scholar or mage order I don't really remember.
Anyone knows?

 

*searching reading list*

 

..... let me put my tent here.

 

https://www.novelupdates.com/series/grimoire-x-reverse-reincarnated-demon-romance-tale/

 

just when I found it -.-
oh well~