It's pretty cute but he really is a bit childish for a reincarnated. Maybe this is like "By the grace of the gods" where the reincarnated's mind will retain a little bit of its childishness.
Kraim sure looks happy even though his target was stolen. Also, why did the mc choose to lie using Athena, couldn't he just say that he was about to be a knight to Ein.
He is a gifted being that was LIKED by multiple gods of reincarnation but they still put him in a trashy world and destined to loss his parents AGAIN. This sucks, they're just torturing the poor kid by not letting his soul free when he died back in his first life. It could have been a little bit...
Some people forget that time flows differently in the place their in and that his master is a god so he will most likely return home like nothing happened and only a few hours had passed.