Who is Clytemnestra (from Electra) from Euripides V and what is their importance?

Clytemnestra was Agamemnon's wife and Electra and Orestes' mother. Her sister was Helen of Troy. While Agamemnon was away at war with Troy, Clytemnestra was unfaithful. She had an affair with Aegisthus. When Agamemnon returned, she and her lover murdered him. Clytemnestra and Aegisthus now rule Argos jointly, and when she is lured to Electra's home, she defends her actions by saying that Agamemnon deserved death for sacrificing one of Clytemnestra's daughters for victory at Troy, and also for bringing another woman home with him. Electra refuses to accept Clytemnestra's arguments, citing that Clytemnestra has doomed her children to poverty and exile while she lives in luxury. Electra and her brother Orestes kill their mother, and although they are wreaking revenge, Electra is punished by banishment to another land, and Orestes faces trial in Athens.