The Nāgas would be the followers of Virūpākṣa (Pāli: Virūpakkha), on the list of 4 Heavenly Kings who guards the western route. They act as guards upon Mount Sumeru, protecting the dēvas of Trāyastriṃśa from attacks with the asuras. In Thailand and Java, the nāga is actually a rich underworld https://128.199.208.170/