My favourite novel of all time. I have no idea why (cough).
Seriously though, MC is incredibly badass. Especially later on when he goes into berserk "whoops I'm leaking black miasma" mode.
Est is the best character, you should know that in advance.
Prepare to be depressed when a massive bombshell is dropped so early on (v1c5)
The witch who summoned them (a child) seems emotionally unstable. At one point when the other 4 summoned humans are eating around a table as their roles are being explained. One of the men shouts at the witch and blames her for getting them stuck in the world. That's where you find out she hates humans, but you don't yet know why.
A little later on, she asks the MC to comfort her (basically hug her) in front of everyone. So he does so whilst stroking her head and saying comforting words. As he breaks free, the girl looks down and mutters "mama... papa" leading to the possibility that the adventuring guild the MC set up before he was summoned, may have killed the girls parents
He sells his really rare and expensive sword he used from his battle with the demon God to a local village shop for barely any money (something like 3 coppers). So you think he's stupid, since selling it to a collector would fetch him more money. Then in the second interlude, you find out that he sold it to the village as they were having money problems. So he essentially gave them something extremely expensive to sell if they needed it
Since he possesses the physique of the scion of light, he is naturally kind natured and unselfish. So he does things that may seem strange, or does not benefit himself. For instance, when he gave up the light element spiritual stove because he felt it might benefit the entire alliance more than just his squad.
This "gap" I mention is the fact that he can't be mean or think badly of others. This is why some people think he has no personality, when in fact he just has a gap in his own