All twelve months are related to twelve Adityas as described in Bhagvatam by Sri Sūta Gosvāmī to Śrī Śaunaka.
SB 12.11.33 — My dear sage, Dhātā as the sun-god, Kṛtasthalī as the Apsarā, Heti as the Rākṣasa, Vāsuki as the Nāga, Rathakṛt as the Yakṣa, Pulastya as the sage and Tumburu as the Gandharva rule the month of Madhu.
SB 12.11.34 — Aryamā as the sun-god, Pulaha as the sage, Athaujā as the Yakṣa, Praheti as the Rākṣasa, Puñjikasthalī as the Apsarā, Nārada as the Gandharva and Kacchanīra as the Nāga rule the month of Mādhava.
SB 12.11.35 — Mitra as the sun-god, Atri as the sage, Pauruṣeya as the Rākṣasa, Takṣaka as the Nāga, Menakā as the Apsarā, Hāhā as the Gandharva and Rathasvana as the Yakṣa rule the month of Śukra.
SB 12.11.36 — Vasiṣṭha as the sage, Varuṇa as the sun-god, Rambhā as the Apsarā, Sahajanya as the Rākṣasa, Hūhū as the Gandharva, Śukra as the Nāga and Citrasvana as the Yakṣa rule the month of Śuci.
SB 12.11.37 — Indra as the sun-god, Viśvāvasu as the Gandharva, Śrotā as the Yakṣa, Elāpatra as the Nāga, Aṅgirā as the sage, Pramlocā as the Apsarā and Varya as the Rākṣasa rule the month of Nabhas.
SB 12.11.38 — Vivasvān as the sun-god, Ugrasena as the Gandharva, Vyāghra as the Rākṣasa, Āsāraṇa as the Yakṣa, Bhṛgu as the sage, Anumlocā as the Apsarā and Śaṅkhapāla as the Nāga rule the month of Nabhasya.
SB 12.11.39 — Pūṣā as the sun-god, Dhanañjaya as the Nāga, Vāta as the Rākṣasa, Suṣeṇa as the Gandharva, Suruci as the Yakṣa, Ghṛtācī as the Apsarā and Gautama as the sage rule the month of Tapas.
SB 12.11.40 — Ṛtu as the Yakṣa, Varcā as the Rākṣasa, Bharadvāja as the sage, Parjanya as the sun-god, Senajit as the Apsarā, Viśva as the Gandharva and Airāvata as the Nāga rule the month known as Tapasya.
SB 12.11.41 — Aṁśu as the sun-god, Kaśyapa as the sage, Tārkṣya as the Yakṣa, Ṛtasena as the Gandharva, Urvaśī as the Apsarā, Vidyucchatru as the Rākṣasa and Mahāśaṅkha as the Nāga rule the month of Sahas.
SB 12.11.42 — Bhaga as the sun-god, Sphūrja as the Rākṣasa, Ariṣṭanemi as the Gandharva, Ūrṇa as the Yakṣa, Āyur as the sage, Karkoṭaka as the Nāga and Pūrvacitti as the Apsarā rule the month of Puṣya.
SB 12.11.43 — Tvaṣṭā as the sun-god; Jamadagni, the son of Ṛcīka, as the sage; Kambalāśva as the Nāga; Tilottamā as the Apsarā; Brahmāpeta as the Rākṣasa; Śatajit as the Yakṣa; and Dhṛtarāṣṭra as the Gandharva maintain the month of Iṣa.
SB 12.11.44 — Viṣṇu as the sun-god, Aśvatara as the Nāga, Rambhā as the Apsarā, Sūryavarcā as the Gandharva, Satyajit as the Yakṣa, Viśvāmitra as the sage and Makhāpeta as the Rākṣasa rule the month of Ūrja.