During the time of Svayambhuva Manu, these sons all became the demigods collectively named the Tusitas. Marici became the head of the seven rsis, and Yajna became the king of the demigods, Indra

Expressions researched:
"During the time of Svāyambhuva Manu, these sons all became the demigods collectively named the Tuṣitas. Marīci became the head of the seven ṛṣis, and Yajña became the king of the demigods, Indra"

Srimad-Bhagavatam

SB Canto 4

During the time of Svāyambhuva Manu, these sons all became the demigods collectively named the Tuṣitas. Marīci became the head of the seven ṛṣis, and Yajña became the king of the demigods, Indra.

SB 4.1.8, Translation and Purport

During the time of Svāyambhuva Manu, these sons all became the demigods collectively named the Tuṣitas. Marīci became the head of the seven ṛṣis, and Yajña became the king of the demigods, Indra.

During the life of Svāyambhuva Manu, six kinds of living entities were generated from the demigods known as the Tuṣitas, from the sages headed by Marīci, and from descendants of Yajña, king of the demigods, and all of them expanded their progeny to observe the order of the Lord to fill the universe with living entities. These six kinds of living entities are known as manus, devas, manu-putras, aṁśāvatāras, sureśvaras and ṛṣis. Yajña, being the incarnation of the Supreme Personality of Godhead, became the leader of the demigods, Indra.