In the quest completion dialogue's first text box:
"Erichthonios: I knew you that you were no mere mercenary, but to make such clean work of the hippokampos... Seasoned fighters scarcely have occasion to visit Pandæmonium, let alone display their skills. Mastery takes all forms, indeed."
It seems like there's an extra "you" right after "I knew..." in the first sentence. Even with it in, it reads awkwardly if left in.