Não está claro.
Algumas das possibilidades são Littlefinger, Cersei e Jaime.
The obvious answer is Cersei Lannister, as Arya has been out to get her since Season 1 for her role in Ned Stark's imprisonment (which ultimately led to his death) and more tragedies on her house. The Queen of the Seven Kingdoms has green eyes, both in the A Song of Ice and Fire books and the show Game of Thrones.
Who Has Green Eyes on Game of Thrones? - HarperBazaar
Isso parece provável, mas existem outras possibilidades, como Petyr.
The prophecy may also refer to Littlefinger (a.k.a. Petyr Baelish),
whom Arya already killed in Season 7. He's said to have gray-green
eyes in the books. (In real life, however, actor Aiden Gillen has blue
eyes.) Maybe Arya has already fulfilled her prophecy and sealed the
deal with the Night King as her victim.
Plus, consider the order of eye colors Melisandre says to Arya. In
Season 3, the order was brown, blue green, but in last night's
episode, the order was brown, green, blue. Perhaps the brown and
green-eyed kills had already happened and the blue-eyed takedown was
the final piece of the puzzle.
Who Has Green Eyes on Game of Thrones? - HarperBazaar
A opção final considerável é que se refira a Jaime e Cersei.
As Cersei's twin brother, Jaime also has the green Lannister eyes, at least in the ASOIF books. Some fans theorize that Arya will kill the Kingslayer and then use his face to kill his sister. That idea also aligns with the valonqar theory Cersei received as a child, which says she'll die at the hands of her little brother.
Who Has Green Eyes on Game of Thrones? - HarperBazaar
Felizmente, receberemos alguma confirmação posteriormente na série.