Was browsing randomly so here I am? Gave it a quick read, this is a 4 star series. The MC himself (not an isekai) is a well established mage who trained only in the barrier arts. Why? Well he can't use anything else as he has affinity for this ability alone. Burdensome to most but he managed to train intelligently which led to him becoming a grand user of barriers themselves. Imagine a caveman with 0 ATK points but maximum defense, similar to the past anime show character, Maple Shield girl. He is not selfish, greedy, or anything of the sorts. The dude is just chill towards everythingand everyone as he seeks to live a chill relaxed life. Story wise it could be better as there are a lot of harem suggestions, but I can make do with it as we got an entertaining series.

His personality is similar to Liam in the space Isekai or the other guy who summons...cows.