Nandi was Shiva’s vahan.He was His most faithful attendant.

Though it was Parvati who was His inseparable self, another being also loved to be by His side, at all times. Nandi.
Nandi was Shiva’s vahan.He was His most faithful attendant.
Nandi had the body of a human but the head of a bull. To make matters more intricate, the human part was built like a bull; the finest and most steely physique, and the bull head could think in the wisest manner possible. It was like magic. But then, that’s what the denizens of the jungle were. Magical creatures.
And Nandi had been declared by Shiva as the chief denizen, the Top Gana. Nandi was His best friend, His loyal devotee, and His vehicle for transport, all rolled into one.
He was Shiva’s ride, so to speak, but even when they were not journeying, Nandi would seat himself at the outer gates of Shiva’s chamber; He thought of himself as a guard, and was indeed, the most formidable obstacle to anyone who wanted to reach Shiva.
He was never off duty.