Guild no Zatsuyougakari ga Shin no Kuromaku Deshita: Kakureta Sainou de Anyaku Musou

Tenes, the illegitimate son of a powerful nobleman, endures a childhood defined by isolation and scorn. Amidst the cruelty, only Fiona—the daughter of her father's legitimate wife—treats him with genuine warmth, offering him the familial bond he has always been denied. However, tragedy eventually tears them apart. Branded as incompetent, Tenes is exiled to the countryside, while Fiona is thrust into the perilous center of a fierce succession struggle for the emperor's throne. Determined to protect her at any cost, Tenes resolves to fight back against the twisted rules that govern their world. Armed with his sharp intellect and abilities long abandoned by the gods, he begins to challenge the very foundations of society alongside a group of formidable companions. To the outside world, he appears to be nothing more than an unremarkable errand boy running trivial tasks for his guild. In reality, this seemingly dull youth is the hidden mastermind orchestrating a dark organization plotting to overthrow the world itself.