Forgotten Title Looking for a story about a dungeon guide

I'm trying to find a story I read a while back about a man who has a job leading new adventurers into the local dungeons. In this world, everyone is born with abilities that decide if they can be adventurers or not and because of his constantly draining energy from him, he can't get strong enough but also has money problems because he always feels like he starving. While leading a new group into his dungeon they end up fighting and killing a goblin king and the protag ends up accidentally eating it's monster core (or something similar) and discovers that instead of dying like most would he can get stronger that way.

Other details I remember are that he has a sister he's trying to help in school who is trying to become an adventurer. Although I think they use a different word for it. I also remember that the author at one point started a rewrite of the series because of reader complaints about some mechanics and story events that didn't make sense. I'm fairly sure this wasn't a Japanese story either.

Edit: The story is also more of a modern setting with cars and skyscrapers rather than a medieval or traditional fantasy setting.

 

Berserk of Gluttony

...or maybe not. I don't remember some fo those details.

 

No, I tried reading that one as well but while they share some themes they are very different. And like I said I'm pretty sure the story I read wasn't Japanese

I suppose I should have also mentioned the story I'm looking for seemed to be more of a modern setting with cars and technology rather than medical like Berserkof Gluttony.
Thank you for trying though.

 

I forgot the name but that’s on rrl, hasn’t updated for a long while though

 

Yep! I just managed to dig it out of my history on rrl and found the author. Apparently, that version of the story has died but his first version is still on going. Guess I'll try that and see if I enjoy it. Thank you for the help!

 

I think you might be mixing bits of Berserk of Gluttony together with this.

Edit: bleh, a few seconds too late.

 

Summon @Tsuru55 who always recommend and even succesfully pushed me reading Andur's works :"

 

Yea apparently some people complained to the author that it was too much like Gluttony so he seems to have dropped that. But thank's for the help.

 

Beside andur i don't have a lot of rrl that i like right now. I never heard about this story. Also i don't understand why you summoned me. Because you thought i know a lot of RRL series ?