Nathan

Nathan Mahler is a chevalier, although it is kept a mystery whose chevalier he is.

Plot
Unlike the other chevaliers, Nathan rarely participates in battle. In the opening credits of the final season, Nathan is shown fighting with Saya though they never do in any episode. He plans not only to destroy Saya, but to do it in a "stage" prepared only for the occasion. This desire results in his stopping some battles between Saya and his brothers, much to their annoyance.

Towards the end of the series, while talking with Amshel, Nathan states that the world exists to showcase Diva's beauty, as was predestined before she was born. When Amshel says Nathan talks like he was there, Nathan implies he was and that before Diva and Saya were born, there was their "mommy" and her faithful chevalier. Nathan later tells Saya that the only thing Diva actually wanted was to have a family. After Diva's death, Nathan asked that Saya kill him, changing into his chiropteran form and allowing Saya to slice through him with her sword, although he is not seen crystallizing.

At the end of the series, he is seen in his human form amongst some reporters outside of Van's trial, without explanation of how he survived. It is thought, however, that Nathan may have been the chevalier of Saya and Diva's mother and was therefore not affected by Saya's blood.

Abilities/Power
Behind his seemingly effeminate and lackadaisical manners, Nathan may be the most powerful of the chevaliers and will assert his dominance over his younger "brothers" if he feels he needs to. He is the only one of Diva's chevaliers who can make Amshel back down if he chooses to, and the only one Amshel rarely attempts to manipulate.

Trivia
In the original Japanese series, Nathan often speaks in a manner usually employed by the feminine gender, such as using kashira and wa. In the Sony English dub, this is represented by Nathan speaking in the manner of a stereotypical homosexual character.