Uttamouja 3 will be the son of the future Sāvarṇi (Savarni) Manu.

Brahmāṇḍapurāṇa (Maharṣi)(3.1.71.)
Garuḍapurāṇa(1.87.39.)

According to the Viṣṇu Purāṇa (Vishnu Purana), Uttamouja was the son of Brahma Sāvarṇi (Savarni) Manu.

Mārkaṇḍeyapurāṇa(94.15.)
Viṣṇupurāṇa(3.2.28.)