For those who have not completed games in the Xenoblade Chronicles series, this page contains spoilers regarding the plot. Discretion is advised.
Emperor Niall Ardanach (Japanese: ネフェル・エル・スペルビア, Neferu Eru Superubia) is the Emperor of the Ardainian Empire in Xenoblade Chronicles 2. He is the younger cousin to Special Inquisitor Mòrag, though the two were raised together by his father and consider each other siblings. He is also a Driver, and Aegaeon is his Blade. He can be found at the Throne Room in the Hardhaigh Palace until Chapter 6.
Despite his young age, Niall is wise beyond his years and calm. He seeks to rule Mor Ardain through more peaceful and diplomatic means, as opposed to the more militaristic means of his predecessors. This trait, however, is not shared by all members of his council, and some even disobey his orders to maintain military dominance. He cares about the well-being of his people, and is willing to aid in the evacuation of the Mor Ardainian Titan, even in the face of Malos's assault, and nearly died defending Urayan Queen Raqura and Rex's party from Bana's assault. While his and his sister's positions keep them apart, it is clear they care for each other, and Niall depends and trusts Mòrag a great deal.
Niall comes to the Indoline Praetorium on behalf of the Empire to the world summit of leaders, where he assures Queen Raqura that they are investigating the incident on Temperantia. He later confides in Mòrag that he wishes to give half of the control over the Gormott Province to the Kingdom of Uraya as compensation for the incident.
He and Raqura have another summit on the Empire's Titan battleship, where Bana plans to assassinate both leaders. He is thwarted by the party; however, in a last-ditch attempt to kill everyone on board, Bana activates an explosive device in Giga Rosa. Niall orders Aegaeon to protect everyone, and goes to stop Bana, but is unable to prevent the explosion, seemingly killing him and sending Aegaeon back to his Core Crystal.
After enlisting Dromarch to distract the others, Nia is able to revive him. He officially designates Mòrag to accompany the Aegis to the Kingdom of Tantal to protect her, and gives her Aegaeon's Core Crystal.