This show is a decent concept with poor execution.
My pet peeve is frustrating shows, and Rin (the main character) is completely frustrating. At every turn he makes almost the dumbest decision possible and wins through with nothing more than spirit, learning nothing in the process. Yukio, Shiemi, every other supporting character, they are all fine. oh wait, the paladin guy is worthless too. Unbelievably worthless.
A lot of scenes feel like they could have been better written. The pacing of the show sometimes feels like it's falling over itself to escalate the action in lieu of interesting plot.
This is honestly not a very good show. Worth watching if you're a current season watcher, but not worth going back and seeing later.