Plenty common IRL too whenever teachers are allowed to set scores and such on their own when not supervised, like in sweden for example.
Teachers playing kingdoms with their classes, dishing out punishment in the form of lowered grades for those they don't like..
If a student outperform them which really aint all that rare, they usually shower that student with heaps of failing grades.
They also often teach things wrong, creating handicaps in the students that actually believe their lessons.
(Although unsure if that's caused by incompetence or them intentionally trying to avoid having someone surpassing them.)
Issues like that are nowhere near as bad in the avg non-swedish school within sweden.
Genderdiscrimination runs rampant aswell with how tests get bit over a full grade higher on average if you write a female name on it compared to a male name.
Yes, that's been confirmed year after year for well over 30 years now, checking such stuff is one of the purposes for the national tests.
Been told it's well over 50 but personally couldn't be bothered with digging even further back through all the official documents,
initially went on to try find out when it started or atleast grew to that point.
Kinda funny with despite how much is documented by the government and available to the public, hardly anyone ever check them over to see if for example feminist statements carry any weight at all.
(By the way those statements are groundless, at best based on specific numbers ignoring their circumstances but common enough with some or all fabricated numbers.)
Thoroughly checking sources work well for spotting lies, not least the feminist ones. (Mind that lies are often made so that they shouldn't look too off to someone that just skimmed through the source.)
Anyways back to the story, seems the guilds internal structure is friendly to those that wants to be a big fish in a small pond, and while it might be fun to trample someone like that..
They'd usually try find ways to get revenge no matter how much they deserved what they got, let's see if this one head down that route too and what method is used since he's outmatched in open combat.
Social natures ranging from nasty rumors to actually framing them of crimes, covert natures ranging from theft to poisoning.. Plenty of ways to try get revenge for them even if they no longer hold any influence over your scores/grades and such.
(Laxatives are rather popular for revenge by poison IRL, revenge aint necessarily about killing but quite often about causing some kind of suffering, preferably untimely for the victim.)