Review Detail of AngelWings in Nightmare's Call

I don't know what other people are talking about but I literally don't understand what's happening at all. First they say that the MC's pretty mature and can stay calm next they say that he has a past life, without mentioning what he was and adding occassional comments about how is old world was more advanced. After somewhat revealing his past life, he starts calling his friends 'kids'? And about his nightmare world i'm extremely extremely confused