Itsuwari no Dragoon III

is the third volume of the Itsuwari no Dragoon light novel series, written by En Mikami and Illustrated by Yu Shiina. It was released under the Dengeki Bunko Imprint in April 2010.

Synopsis
An unexpected visitor comes to the Knights Academy. Sarah, the princess of the Principality of Urs, who is a member of the Marine Union. She says she's also Jean's fiancée. Tiana explodes, perhaps because she couldn't get angry at her unrestrained words and deeds. Jean gets angry with his son-in-law. Eventually it develops into a match between the two who bet Jean !? On the other hand, the Knight Academy who wants to embrace a passive Principality on the Imperial Front against Legalion applies for an alliance. However, there is a conflict of interest with the empire, which makes similar proposals to the Principality. As a result, the ally is decided by the game due to the drunkenness of the Grand Duke. The game was "Planetta", a competition in which dragon knights from each country compete for their skills. Jean will meet the masked man again !?

(source: Bookwalker JP - Translated)