Fiver
From Wolfire Games Wiki
Fiver was a guard at Rock Hall when Turner staged his bloodless coup against the king Hickory.
He was left in charge as Turner traveled to the Wolf's Den to kill Ash, the alpha wolf.
At the end of Lugaru, it is unclear whether or not Fiver is still in a seat of power amongst the Rabbit government.
Trivia
Fiver is also the name of a Rabbit from Watership Down. This naming coincidence was likely intentional as an homage.