There are three kinds of demigods - the Adityas, the Vasus and the Rudras - beneath whom are the other demigods, like the Maruts and Sadhyas
SB Canto 7
O my dear King, Hiraṇyakaśipu was always drunk on strong-smelling wines and liquors, and therefore his coppery eyes were always rolling. Nonetheless, because he had powerfully executed great austerities in mystic yoga, although he was abominable, all but the three principal demigods—Lord Brahmā, Lord Śiva and Lord Viṣṇu—personally worshiped him to please him by bringing him various presentations with their own hands.
In the Skanda Purāṇa there is this description: upāyanaṁ daduḥ sarve vinā devān hiraṇyakaḥ. Hiraṇyakaśipu was so powerful that everyone but the three principal demigods—namely Lord Brahmā, Lord Śiva and Lord Viṣṇu—engaged in his service. Madhvācārya says, ādityā vasavo rudrās tri-vidhā hi surā yataḥ. There are three kinds of demigods—the Ādityas, the Vasus and the Rudras—beneath whom are the other demigods, like the Maruts and Sādhyas (marutaś caiva viśve ca sādhyāś caiva ca tad-gatāḥ). Therefore all the demigods are called tri-piṣṭapa, and the same word tri applies to Lord Brahmā, Lord Śiva and Lord Viṣṇu.