Ja'rod

Duras's powerful father who betrayed the defense codes of Khitomer, allowing 4,000 Klingons to be massacred by Romulans there in 2346 including Worf's father Mogh. Incredibly, Ja'rod's son Duras later altered 'newly found' records to blame Mogh for the traitorous acts. He also sired Lursa and B'Etor.