The Germanic word(s) for "king" are unique among Indo-European languages.
Whilst most IE words for king can be sourced to the Proto-Indo-European
*h₃rḗǵs (see: Latin rēx, Sanskrit राजन् [rā́jan], Irish Rí), the etymology
of "king" (German König, Danish Konge, Old English Cyning) is different; it
comes from Proto-Germanic *kuningaz, composed of the words *kunją + *ingaz,
lit. "someone of the family". This suggests something took place uniquely
within early Germanic society that altered their conception of kingship,
the nature of which is evident by the fact that their words for it are
cognate with "kin" or "kinship", "family" and "clan" — all ultimately from
PIE *ǵenh-, "to beget, give birth". Contrast this with the connotations of
rēx, such as "ruler", "royal" and "mighty". Germanic kings draw their
legitimacy "from the people" as kin, rather than from above as ruler.