I'm not going to answer the other stuff
I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched C-beams glitter in the dark near the Tannhäuser gate. All those moments will be lost in time... like tears in rain...
Still not a signature, huh?
As for the origins, based on the 'Meet The Pyro' video, and this idea of 'Pyrovision'. Where everything he/she sees burning is bubbles and rainbows, that their psychology is definitely pretty messed up. Maybe he/she is a highly disturbed soldier from a previous war scenario, or as some other people have suggested, maybe he/she is just a robot prototype gone completely wrong. Maybe his/her purpose was to hug people and stuff, but someone tapped into his/her technology or something. I dunno. xDD.
I post stuff with my monitor turned off. Yes, I have acquired these certain set of skills over a life-time of inter-webbing.
Live long and prosper! .___.