It is his battle cry. Stan Lee says that he just liked the sound of it. It is not proper Latin (Namor is "Roman" backwards) but he is basically saying something like "Despotic King!" It is unclear if this is an insult against his enemies or simply a case of him announcing his own presense as the King of Atlantis.
Attuma and General Krang are his biggest foes I would say, in that order.
el conejo rex
T-rex! If you ask a 5 year old he will say T-rex. If you ask an 80 year old they will say tiger or T-rex.
The correct way to say it is T-Rex and Tyrannosaurus and yes T-Rex is short for Tyrannosaurus.
I am the king
a rex was dumb that a spinosaurus could kill it is all i can say.
You say 'Tuus rex est.'
rex regum
Rex Iudaeorum
Rex mei mundi.
the same way in English
Yes, it is correct. I always say that! You always say that! She/he always says that! They always say that! We always say that! just to add, My teacher always says that!