Fxxk in Guide

Nam Jin-Seo, who developed his esper skills at a young age and worked as a trainer at the center for nearly 20 years, was tasked with intensively training Go Won-Hun, who developed his esper skills later than others, at the center director's request to quickly train him as an S-rank esper and send him into the field. Go Won-Hun, experiencing his first taste of guiding and discovering a world of his own, became obsessed with him from that day on.

"Senior, you're an A-rank esper, so you must have been very helpful to other espers, too. Why can't you do anything better than this?"

(Source: Lezhin, translated)