World's most efficient cortisol machine
Panzer was one of the first two documented people to arise, alongside Beck. As such, the records show them sharing a birthday! This arrangement seems to suit the two of them fine, and Panzer specifically has been going at a fairly steady clip since that day.
Nobody claims particular ownership over the body or brain; Panzer just happens to be the paperwork guy. While it's a bit of a stretch to call anyone a particularly functional adult, Za appears to be the closest we've got, and tends to handle major backend and paperwork manners--name changes, data entry, general bookkeeping--you name a bureaucratic function, and the chance that Panzer's the primary handler of it is typically around 95%.
More poetically, he's a 'barrier'; his skills include, but are not limited to: sitting around taking punches, sleeping a lot, and harping on people to do their own jobs. While it kind of sounds like being lazy, his job, like all others, are essential. And he is excellent at it, though Alcatraz has a rather sour attitude toward him. Part of this is a partisan approach to internal politics--Panzer is the helmsman of the Jovian group, which includes Lio and Ruination, among others.
Panzer's personal projects are usually in the orbit of Transformers. Both Panzerverse (shocker!) and Risen AU are straight from his hand. Outside of that, his work encompasses Mawheart and the Tank Museum.