Riecko

Rupert

German variant of Robert, from Old German Hrodperht

Wolter

Dutch variant form of Walter

Aaric

No documented meaning in the sources checked

Alaric

From the Gothic name *Alareiks, "ruler of all"

Caesar

A title used by Roman emperors, deriving from Julius Caesar.

Derek

English short form of Diederik, from the Germanic Theodoric, meaning "people-ruler"

Derrek

A variation of Derek, meaning 'the people's ruler' or 'gifted leader'.

Djerry

Gerwin

Dutch masculine given name from Germanic ger (spear) and win (friend)

Heiko

Low German and Frisian diminutive of Henrik.