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.
(..) If only I were otherwise. If you are Tyrion Lannister, why shouldn't I kill you to pay your family back for what it did to mine? You want revenge against the Lannisters? I killed my mother Joanna Lannister on the day I was born. I killed my father Tywin Lannister with (..)2015 TvShow: Game of Thrones Title: Hardhome Season: 5 Episode 8