His heir is his niece, L'Arachel, whom he has lovingly raised ever since her parents perished when she was a young girl. During the game's events he is portrayed as pious and kindly. Mansel has high authority over both political and spiritual matters.
Mansel first appears in Chapter 19, where he greets L'Arachel and her guests to Rausten Castle. During the darkness of night, Riev and remnants of Grado's forces infiltrate the palace to shatter the final Sacred Stone. Riev also wanted to exact revenge on Mansel for his excommunication. Ephraim and Eirika protect Mansel from the attackers.
After the battle, Mansel loans Ephraim and Eirika the Rausten's Sacred Twins, Latona and Ivaldi. He is aware that he is breaking tradition as they were to never be used apart from the occasional ascension ceremony, but knows that the Demon King must be defeated at all costs. He asks them to return them after the Demon King is defeated, and gives them some funding for their mission.