In Latin, it depends on how it is used in the sentence.
"reges" is probably what you want. It would be translated simply as "kings". The other cases are more specific, e.g.,
"regum" -> "of the kings"
"regibus" -> "to/for the kings"
And the singular is "rex".
BTW, "We three kings of Orient are" would be translated "reges tres orientis sumus."
"Dead king" in English translates to "mortuus rex rgis" in Latin.
You say 'Tuus rex est.'
Rex Iudaeorum
rex regum
Filia regis is daughter of a king
There is no Latin word for princess. The nearest is regis filia which is the daughter of the king.
Rex mei mundi.
Rex bestiarum (I think)
there is no latin king
Liberi regis lucis aeternae.
Rex is latin for King
Youtube it, they have videos how to do a Latin King handshake