Aeschylus continued his emphasis on the polis with The Suppliants in 463 BC (Hiketides), which pays tribute to the democratic undercurrents running through Athens in advance of the establishment of a democratic government in 461. In the play, the Danaids, the fifty daughters of Danaus, founder of Argos, flee a forced marriage to their cousins in Egypt. They turn to King Pelasgus of Argos for protection, but Pelasgus refuses until the people of Argos weigh in on the decision, a distinctly democratic move on the part of the king. The people decide that the Danaids deserve protection, and they are allowed within the walls of Argos despite Egyptian protests.  The 1952 publication of Oxyrhynchus Papyrus 2256 fr. 3 confirmed a long-assumed (because of The Suppliants' cliffhanger ending) Danaid trilogy, whose constituent plays are generally agreed to be The Suppliants, The Egyptians and The Danaids. A plausible reconstruction of the trilogy's last two-thirds runs thus: In The Egyptians, the Argive-Egyptian war threatened in the first play has transpired. During the course of the war, King Pelasgus has been killed, and Danaus rules Argos. He negotiates a peace settlement with Aegyptus, as a condition of which, his fifty daughters will marry the fifty sons of Aegyptus. Danaus secretly informs his daughters of an oracle predicting that one of his sons-in-law would kill him; he therefore orders the Danaids to murder their husbands on their wedding night. His daughters agree. The Danaids would open the day after the wedding.  In short order, it is revealed that forty-nine of the Danaids killed their husbands as ordered; Hypermnestra, however, loved her husband Lynceus, and thus spared his life and helped him to escape. Angered by his daughter's disobedience, Danaus orders her imprisonment and, possibly, her execution. In the trilogy's climax and denouement, Lynceus reveals himself to Danaus, and kills him (thus fulfilling the oracle). He and Hypermnestra will establish a ruling dynasty in Argos. The other forty-nine Danaids are absolved of their murderous crime, and married off to unspecified Argive men. The satyr play following this trilogy was titled Amymone, after one of the Danaids.

Answer this question "What is his part in the story?" by extracting the answer from the text above.
Danaus rules Argos. He negotiates a peace settlement with Aegyptus, as a condition of which, his fifty daughters will marry the fifty sons of Aegyptus.