Someone on Reddit translated the text
Wolf
The prince's shinobi, in the prime of life. Cold and reticent, bound by his code, the Wolf does whatever it takes to fulfill his duty, and kills without pity nor mercy. An exceptional ninja.
During this tale, he is defeated by the commander of the Ashina, losing both his young lord and his left arm. Replaced with a prosthetic limb, the Wolf must wager his life to regain what was stolen and protect his master. The shinobi code is absolute, and guides him towards his revenge.
Prince
The sole descendant of an ancient lineage. Alone on this earth, much like his shinobi. The prince was raised as the adopted son of the Ashinas' chief vassal, Lord Hirata. Calm and brave beyond his years, the dignified prince is abducted by the commander of the Ashina for his peculiar bloodline.
The Sculptor (Busshi of the Dilapidated Temple)
An aging man with no left arm. A silent and unsociable hermit. Secluded in a ruined temple deep in the mountains, he continually carves countless statues of the wrathful Buddha. Finds the defeated shinobi, thereafter offering his aid.
Emma
A young healer who appears before the Wolf as he awakens in the dilapidated temple. Aids the Wolf at the behest of her master, but her master's name and intentions remain unclear. Those quiet eyes gaze at the Wolf as if searching for something, and brim with a faint sorrow.
Ashina Genichiro
Genichiro is the grandson of the legendary swordsman Ashina Isshin. Not of legitimate birth, but a commoner. Nevertheless, holds a profound duty towards his clan. In order to defy the decline of the Ashina, he abducts the young prince to make use of his unusual powers. The Ashina are on the brink of extinction. This country must be protected, even if through supernatural means.
Owl
The wandering shinobi Owl is an exceptional warrior, with no master. Picked up the starving Wolf on the battlefield by chance, raising him into a shinobi, beating his own skills into him. However, the one final thing he imparted into Wolf...
The shinobi's iron code is absolute. Never forget that.
Pretty much what was there on the website after the announcement at E3 2018. I think they added Emma, Owl and the name of Genichiro. I remember Vaati talking about most of this stuff in the first video he did about Sekiro after the announcement.