Claus is a 15 year old vanship racer/courier and is the son of the famous Hamilkar Valca who died crossing the grand stream. His navigator is Lavie and they both hope to one day cross the grand stream like their fathers tried to. Claus is a very skilled pilot and is praised by Dio for his skills. He is brave and always wants to complete his mission no matter what it is or where it takes him.

At the start of the series Claus is a courier but he is taken to the Silvana by one of his missions and ends up becoming a fighter pilot for the Silvana because he wants to protect everyone.

He seems to be the real ladies man, getting Tatiana,

Lavie, Alister, and Sophia to have crushes on him. Sophia makes out with him to get out her sexual frustration (I don't know why she kissed him but let's assume she had all that built up because Alex neglects her feelings)

Claus is like a big brother to Alvis throughout the series. Once she loses Gita she hangs on to him and he makes sure she is always safe.

At the end of the series he crosses the Grand Stream with Lavie and gains control of Exile by reciting the mysteria with Alvis.