He is one of the Pillar Heads in Behemoth's 34th Pillar Division.
Naga is created by Ryuhei Tammura. Even though the Tamura did not specifically explain what inspirations he used to create Naga, Naga's name is assumed to based off the serpent's name, Naga, in Buddhism or Hinduism. He first appears in Beelzebub volume 10 and episode 41. His Japanese seiyuu is Ryoko Shiraishi.
He first appears with Graphel, and he watch Graphel fight Toujou. When Zenjuro's demon power spike up, he tells Graphel that they must assist Hecados. In their confrontation with Zenjuro, Naga and his team charge at Zenjuro, but Zenjuro blasts them with his Zebul blast. Naga uses his ring to teleport his team back to the demon world.
Later in the human world and after Hilda has defeat Yolda and the wet nurses, Naga and his allies teleport to their location. Naga witnesses Hecados strangling Yolda and Hilda intervening by blasting him through the roof. Naga and Graphel follow the battle to the roof. As Oga arrives, he asks Naga about what they would do with Beelzebub. After Naga answers Oga's questions, Oga tells him and the demons that he is Beelzebub's parent and will not let him destroy humanity. Naga challenges Oga, but he allows Oga to complete super milk time time. He has difficulty with Oga; Graphel grabs Oga and tells Naga to finish him off. Before Naga can fire his demonic aura, Oga and Beel use their combined powers to create an explosion that defeats him and his allies.
Naga is known as the water dragon (*need to check), and he can fire demonic aura like energy blasts. This is seen during his fight betweeen Oga and the assistance of Graphel and Hecados.
In the anime, Hecados scene of strangling Yolda in the presence of Naga and Graphel is replace with other demons. Instead, Naga and his two friends appear on the roof where Hilda, Aoi, Toujou, and Oga arrive.