Gregorio is quite the complex character.
He only appeared in Volume 2 and only mentioned a few times in the succeeding volumes.
Thus, we will only be able to speculate Gregorio's character in this one volume.
Honestly, Im not sure if you'll like him or not.
What makes him the MAD lad is because you can't predict what he'll do even if you're allies.
So his acquaintances treats him with caution like a mad guy.
Because Gregorio is so devout to his god, that they'd think he will stab them if ever that god tells him to.
So far, this chapter should be around after half the volume 2.
you can judge if you'll like him cuz there's some solid facts in this volume.
-backstory, before he bacame a crusader
-source of his strength, tricks & blessings
-his fight with the heroes party
-and why spica choose him instead of Ares to teach her