> "And hast thou slain the Jabberwock?
> Come to my arms, my beamish boy!
> O frabjous day! Callooh! Callay!"
> He chortled in his joy.
The poem is written from the perspective of the boy's father, who is clearly proud of his son's accomplishment. The son's name is not given, but he is not anonymous.
It is possible that you are thinking of the "man" who "came to a place called the Tumtum Tree" at the beginning of the poem. While he is not named, he is clearly the protagonist of the story, even if he is not the speaker of the poem. However, even this "man" is not truly anonymous, as he is clearly the boy's father, who later expresses his joy at his son's victory.