In course of describing how Agni (Deity of Fire) entered into water, there had been a mention of a specific kind of Agni that is present within water. According to Paurāṇika (Pauranika; Purana-oriented) thoughts, this fire is called ‘Saha’. Nilakaṇṭha (Nilakantha), the commentator, says that ‘Saha’ is a definitive term for Āpa (Apa), denoting a Deity presiding over Bhūloka (Bhuloka; the earthly world) and Bhuvarloka (the Universe). His wife was Muditā (Mudita), who have birth to another Agni (Deity of Fire) who also came to preside over Bhūloka and Bhuvarloka. Though this Agni is not named at this very point in Mahābhārata (Mahabharata), the commentators have considered the mantra-phrase “Sahasasputro’dbhūta“(along with Ādbhūta, son of Saha) as a proof and decide that the two Agni (two Fire-gods) — ‘Saha’ and ‘Adbhūta’ (Adbhuta) are be one. That is why, the son of Āpa and Muditā is defined as “Bhūpatirbhuvabhartta” (Ruler of the Universe) in Mahābhārata (Mahabharata).
[See Adbhūta]