JokerRex

his trump cards? nah, the system is his Trump card and he can buy many orders and whatnot that he wants with enough fate points – so, basically he's a walking mystery box.

This reminds me of "You're just making up the exercises, my disciple, have you really mastered them?" -

Time to match that energy.......

This is also a valid point, also atleast the author gave us an explanation to look at, instead of most that just says "You use mana like so, as you do it you imagine the source and just F with it until you're able to control it. Once you do that you're one step to becoming a blah blah blah."

Tis more of him using sun wukong as the reference instead of Naruto, Since this is basically wukong's abilities only less power and without the couldrin of fire.

Attack on titans

ever since he rescued that goddess and got this annoying fairy, it's like his IQ did a complete 360-

Thief/Locksmith or rogue basically