Keith has been named the "White Knight", the title given to the ace of the aerial knights, and pilots a custom Sv-262Hs Draken III unit, colored in black with details in gold.
Keith is an exemplary warrior, representative of the best the Kingdom of the Wind's military forces have to offer. Proud and fiercely loyal, he swore to protect his half-brother Heinz Nehrich Windermere despite being the illegitimate son of Gramia Nerich Windermere. Alienated by family and peers at a young age, Keith found solace in his friendship with Roid Brehm. The two fell under the tutelage of Herman Claus and trained to be part of the Aerial Knights. They were excellent swordsmen, and would spar on occasion. They were deeply affected by the destruction of a Windermerian village at the hands of the New United Nations Spacy, and vowed revenge after their people surrendered. As Keith grew into adulthood, he grew distant from his half-brother Heinz. His loyalty never wavered, even as King Gramia VI used the resurrected Protoculture vessel, the Sigur Valens, to further his plans for galactic conquest.
Keith never had much of a relationship with his father, but nevertheless served him as a loyal knight.
Roid and Keith were childhood friends and later, comrades as they joined the Aerial Knights. Their mutual hatred towards the N.U.N.S fueled them throughout their adult life. Keith grew to distrust Roid as he continually exploited his half-brother Heinz Nehrich Windermere for the war effort.
As a boy, Keith swore to his stepmother that he would protect Heinz from harm. However, they grew distant from one another as Keith grew into adulthood.
Keith first encountered Messer's Valkyrie on the planet Al Shahal, and the two shared a fierce rivalry ever since.
Keith first considered Hayate a nuisance, but their rivalry came to a head following several dramatic events in the series.
Keith considers her a traitor to their race.