Serpentine Youth- A kind of Bhavanapati (Mansion-dwelling god) Devanikāya (fourfold habitats of gods);
the class of gods, whose head and face have a bluish black lusture, whose motion is elegant, and who have on thier head an emblem of the hood of a snake. The class of gods who remain at the command of Varuna, Devendra Śakra's Lokapāla (universal guard of the king of the gods of the first heaven).
śiromukkheṣvadhikapratirūpāḥ kṛṣṇaśyāmā mṛdulalitagatayaḥ śirassu phaṇicinhā nāgakumārāḥ.
(TaVā 4.ll)
nāgakumārā nāgakumāno......tabbhattiyā, tappakkhiyā, tabbhāriyā sakkassa deviṃdassa devaraṇno varuṇassa mahāraṇṇo āṇā-uvavāya-vayaṇa-niddese ciṭṭhaṃti.
(Bhaga 3.262)