One of the Asṭavasu (Astavasu; eight Vasus), Āpa (Apa) is a god with a celestial halo. He has four sons, namely –Śānta (Santa), Vaidaṇda (Vaidanda), Śāmva (Samva) and Munivakra. They are entitled to protect the yajña (yajna; ritual sacrifice).
In Brahmāṇdapurāṇa (Brahmandapurana), the name ‘Āyu'(Ayu) or ‘Āya’ (Aya) has been used instead of Āpa. Vaitaṇda (Vaitanda), Sāma (Sama), Śānta (Santa), Skanda, Sanatkumāra(Sanatkumara) — all of them are sons of Āyu or Āya.