Dorium (also called Dorion) was one of the fifty daughters of Danaus who participated in the mass marriage to the sons of Danaus' brother Aigyptos. Dorion would wed Khthonius. That night she slew her husband just as fourty-eight of her fourty-nine sisters did.
When Dorion and the other Danaids who had murdered their husbands they were sent to Tartarus and were forced to carry water from the river Styx in a bowls (or jars according to some) with holes over to a tub which leaks at multiple parts. Dorion and the others were told only when they filled the tub could they wash away their sins. The Danaids continue this essentially impossible task to this very day.
Danaus & An Ethiopian Woman
"Agaptolemus got Pirene; Cercetes got Dorium; Eurydamas got Phartis; Aegius got Mnestra; Argius got Evippe; Archelaus got Anaxibia; Menemachus got Nelo. These seven sons were begotten on a Phoenician woman, and the maidens on an Ethiopian woman"
- Apollodorus, Library 2.1.5