As the other Sons of Fëanor, Caranthir was bound by an oath to recover his father's Silmarils, which had been stolen by the Dark Lord Morgoth. This oath took the seven brothers to Middle-earth during the First Age, where they established realms in exile, waged war against the armies of Morgoth, fought their own Elvish kind, and eventually brought ruin upon themselves.
In First Age c. 420, Caranthir rescued Haleth and her people, the Haladin, as they were besieged by Orcs. When he saw the valour of Men, he offered the Haladin a fiefdom in his lands to the North. However Haleth, wanting her people to serve no lord, thanked him but removed to the Forest of Brethil.
In 472, the disaster of the Nirnaeth Arnoediad ("Battle of Unnumbered Tears") occured, caused by the betrayal of the people of Ulfang. Caranthir lost his realm and was forced to retreat to Mount Dolmed with his surviving brothers.
As a member of the House of Finwë, Caranthir's father-name was Morifinwë ("Dark Finwë", a reference to his dark hair). His mother-name was Carnistir ("Red-faced"). The name Caranthir is the Sindarin translation of his mother-name.
Finwë = Míriel | | Fëanor = Nerdanel | _________________|________________________________________________ | | | | | | | | | | | | | | Maedhros Maglor Celegorm CARANTHIR Curufin Amrod Amras | | Celebrimbor