Budding Ambition

Budding Ambition (野望の萌芽) is an extra chapter included in the 9th volume of the Attack on Titan: Before the Fall manga, written by Ryō Suzukaze and illustrated by Satoshi Shiki.

Overview
A week before the arrival of "The Titan's Son", siblings Xavi and Sharle Inocencio attend a dinner by the Diekmeier family. After dealing with the insults thrown at him and the family, Xavi defeats Abel Diekmeier in a duel; he later tells his father Dario that he will the the sole man to conquer the threat of the Titans.

Summary
Sharle is seen reading in her family's library when Xavi enters. He mentions that she will be accompanying him to a dinner invite with the Diekmeier family the following day. When Sharle asks why, Xavi casually mentions that it would be good for their family to be on positive terms and that the heir to the family, Abel, likes girls. Sharle continues to protest, but Xavi shoots an angry glare at Sharle and says she will obey his orders without question.

While having dinner, Abel notes with surprise to Xavi how he never mentioned having a sister. Sharle uncomfortably smiles while Xavi pays no notice. Abel goes on and ends up insulting both Xavi and Sharle's mother and father; Sharle nervously looks at Xavi, who still does not react. Abel points out a pair of swords given to his family by the king at the time and insinuates that Xavi's is sloppy in comparison to his own. Having had enough, Xavi asks to have Abel teach him. Xavi later defeats Abel and holds his sword at the latter's throat, insulting Abel's high priority on dignity.

Back home, Dario tells Xavi to control his temper and that he had to pay a lot of money to silence the Diekmeier family; Xavi brushes it off by justifying that Abel insulted him. Dario admires Xavi's spirit but again says that he must be stronger. He reveals that "The Titan's Son" will be arriving in a week and that Xavi must prove himself strong enough to conquer the abomination if he plans to lead the entire Military Police Corps. While Sharle panics at the thought of having a Titan in their house, Xavi swears that he (and only him) will be the one to conquer the threat of the Titans.