Humanoids of Krios, long at war with the neighboring Valtese, whose rare empathic metamorphs can bond with and reshape themselves for a chosen partner.
The Kriosians are humanoids of the planet Krios. For centuries they waged war against the people of neighboring Valt Minor, a conflict the Federation helped bring to an end.
The Kriosians occasionally produce an empathic metamorph, a rare individual able to sense the desires of a potential mate and change to suit them, eventually bonding permanently with one partner. Such a woman, Kamala, was meant to be presented to Chancellor Alrik of Valt Minor to seal peace between the two worlds.
In The Perfect Mate, Ferengi passengers released Kamala from stasis too early, and she bonded with Jean-Luc Picard instead. She chose to go through with the ceremony anyway to honour the peace. In The Mind's Eye, a Klingon-held colony called Krios faced a Kriosian rebellion, and the Romulans brainwashed Geordi La Forge in an attempt to blame the Federation for supporting it.