This Manga is a SHONEN BATTLE MANGAThe place is a country of labyrinth in another world.Main character will be fighting with his nakamasJust like Shin Megami Tensei: Persona 4, beside level up to unlock skill, he needed to rise his nakamas' truth points to unlock more skillsHe need to fight battle boss, rescue a Goddess/Aeon/Guardian Force/Eidolon in each Dungeon to use special skillMore important this main character has GUTS and BRAINHis class isn't special or anything, just another Japanese Reincarnator Class like other Japanese, so he must work with his GUTS and BRAIN to fight with his Nakamas to PROTECT EVERYONE as he intended)Okay, so our main character is a workaholic with a demanding boss, who are both together when a bus crash kills them both. Something something isekai something something skill points something something adventurer's guild something something dungeon exploration. Look, you've been here long enough to know how it goes.So, the demanding boss becomes a Valkyrie and the MC, not wanting to work under her, decides to go solo. He soon must choose a class that his character will work as, and decides on "rear guard". However, he soon finds that a rear guard is actually a fairly rare job - and one he may just be able to excel at.