Blackavar is one of the "lesser" rabbits living in Efrafa. Blackavar was an extremely timid rabbit who so hated the oppressive rule of General Woundwort and the Council that he made multiple attempts to escape despite the harsh consequences. On his latest attempt, during Captain Holly's time as a prisoner in Efrafa, he was punished by having his ears ripped.
Following this, he was forced to sit outside of his burrow at every morning and evening silflay, overseen the smarmy and cruel Chervil, as an example to the other rabbits. Bigwig helped Blackavar escape by attacking Chervil, and although Blackavar made it to Watership Down, he did not live long enough to enjoy his newfound freedom. The Efrafan Owsla invaded, and Blackavar died heroically standing up to Woundwort alone.