Pex is a war machine styled after a protogen, being built during a massive world war but being finished too late to participate. Pex or his real classification APEX UNIT-1 is entirely mechanical being created to look like a protogen because "we thought it would look cute" said by the WARP organisation representative.

Pex is now stuck as a peace keeper only allowed to do any real combat against either up-and-coming warlords or idiots playing Kaiju with stolen classified size tech, neither last long