Josef Grunger is a human Grand Admiral, one of the twelve promoted in 2 BBY, and a Star Wars Legends character first appearing in The Glove of Darth Vader (1992), the opening volume of the Jedi Prince young-reader series. After the Emperor died at Endor he seized the planet Gargon, declared himself the new Emperor, and assembled a substantial fleet of Star Destroyers and cruisers by a mixture of coercion and lying.
He offered conditional support to the claimant Trioculus without ever committing to the Central Committee of Grand Moffs, and kept his armada independent after Trioculus died. In 5 ABY he moved on Imperial Center and ran into Grand Admiral Danetta Pitta near Tralus in the Corellian system. Losing the engagement, he rammed his Super Star Destroyer Aggressor into Pitta's Torpedo Sphere, destroying both ships and killing both Grand Admirals.
Catalogue entry. This figure has a verified record here rather than a full write-up — the encyclopedia labels its own depth instead of padding it.