Ambrose Jakis is a major antagonist in the Kingkiller Chronicles by Patrick Rothfuss. Even though Haliax is the main antagonist of the series, Ambrose is the most seen antagonist by far. He is the son of a powerful Baron, and is Kvothe's main rival and enemy at the University.
Ambrose started attending the University a few years before Kvothe did. He became a Re'lar in the Arcanum and a scriv under Master Lorren.
Kvothe first met him at the archives, where he refused to let Kvothe in, since Kvothe had just been admitted. Later Kvothe returned and saw Ambrose sexually harassing Fela. Kvothe called him out and in revenge, Ambrose tricked Kvothe into entering the stacks with a lit candle, causing Kvothe to be banned from the archives.
Kvothe and Ambrose constantly tried to torment and one-up each other. At the Eolian, Ambrose used sympathy to break Kvothe's lute string. Ambrose used his money and influence to prevent Kvothe from finding a patron, and bought out an inn to get Kvothe fired.
Later, Kvothe wrote a song called "Jackass", meant to insult Ambrose. In revenge, Ambrose sent two thugs to kill Kvothe.
At one point, Ambrose stole and broke Kvothe's lute. Kvothe accidentally called the name of the Wind to knock Ambrose over. Ambrose was forced to pay twice for the value of Kvothe's lute, and Kvothe was whipped.
When Kvothe was going to admissions, Ambrose had him poisoned with Plum Blob, which removed Kvothe's inhibitions. He went on a date with Kvothe's love interest, Denna, and took her mother's ring. Kvothe tried to break into Ambrose's rooms and failed, and left behind some blood. Ambrose used the blood to perform malfeasance against Kvothe.
Later, Kvothe had Fela pretend to date Ambrose, so he could break into Ambrose's rooms. Kvothe took the ring back and destroyed the mommet used to perform malfeasance against Kvothe.