Psychtronics is a field of arcanotechnology that deals with using machines to emulate the mentalist parapsychic realms such as as telepathy, mind control, memory manipulation, and emotional manipulation.
In the years before the advent of arcanotechnology and dimensional fatigue events, teratology was the study of abnormalities and biological deformations. In the wake of the second renaissance, it became the study of exomorphs, extradimensional entities, and most prominently, teratomorphs, more commonly and vulgarly known as kaiju.
Orcs record their deeds through symbolic mutilation, scarring and tattoo. Perhaps creating the medium of skin as art, which humans followed later. Perhaps tattoos remind the elves of orcs and make them angry...