The Alchemist/Cloaked man is not Vigo.
Read the Journal of the person's last years animatics.
" discovered a hidden laboratory while running away from a monster. Its stocks are uncommonly plentiful. I observed shelves of alkaloids, crates of silver syringes, piles of protective clothes and a journal signed “Vigo”. Its pages are filled with notes on an ancient force that controls the nature of this place—that shapes it. I also noted a few drawings of the growing cankers I've seen on trees."
"Based on Vigo's calculations, tonight is my last chance. I filled a syringe with the last drops of serum and injected it into my arm."
"I looked for Vigo. I shouted his name with no concern for the monsters lurking about. I need to find him… I picture the scene, etching a canvas of wild lines in my mind, focusing on the moon and I know—something is off. I fed the dead rodent under my pillow."
Why would the cloaked guy (the Alchemist) Look for Virgo if he was Virgo, or follow Virgo's instructions?
we also learn this year from the animations and new journals that he became addicted to the serum and has major arm pain. What do we see the guy do in the animation? Grab his arm in pain.