Etymology: Middle English king of kinges
: a monarch having other monarchs under him: as
a. : an earthly sovereign
this forthright declaration by the king of kings … forms a fitting conclusion to the long story of Justinian's wars — P.N.Ure
b. capitalized 1st K, often 2d K : god , christ 1
the blessed and only Sovereign, the King of kings and Lord of lords — 1 Tim 6:15 (Revised Standard Version)
the deity is treated as the King of Kings — D.S.Sarma