He wasn’t created. He appeared.
The character of Tuna was not planned. Backstory and purpose weren’t factors in his creation, because he wasn’t created. Instead he appeared. He came into being in silence and within Real Tuna’s thoughts, where Reality blended with imagination. Watching a blank screen, one day he stepped out of the faceless world that Real Tuna hated and began existing.
Neither was there a grand event or reason for anything of this sort. He simply is.
He later turned into Real Tuna’s internet persona—Tuna—where that dull personality is put to use. Cool, laid back, no ushering for script. He doesn’t speak much, even makes an effort with the effort being too little and frankly does not need to prove anything.
The persona is treated as a baby of Real Tuna’s by Real Tuna which is not maternal, but more along the lines of treasure. Like she mothered without stunning to contraption limbs orienting her to everything. She does not control him, but she does monitor, ensuring he is safe, permitting him to be her in moments lacking
...words.