He is 'seeking revenge for' his father's murder. [=he wants to harm the person who killed his father]
He swore to 'take (his) revenge on' his enemies. [=to harm his enemies]
The bombing was 'in revenge for' the assassination of their leader.
(..) never going back. We'll get justice for you. If I got justice, my burnt body would hang over the gates of Winterfell. Fuck justice, then. We'll get revenge. Drink. Listen to me. If you're so broken that there's no coming back, take a knife and cut your wrists. End it. (..)2016 TvShow: Game of Thrones Title: The Broken Man Season: 6 Episode 7