• This card's name is a portmanteau of "pyro" and "rex", the latter referring to a Tyrannosaurus rex.
    • It is also possibly a pun on Pyrodex, the first black powder substitute.
  • Like the other "Elemental Lord" cards, this monster's given name is in a unique Western language, in this case Latin (pyro is Greek for fire, while "rex" is Latin for king).