Krios

From Memory Alpha, the free Star Trek reference.

You may also be looking for the planet named after Krios called Krios Prime.

Krios and his brother Valt were the rulers of a vast Kriosian empire, which they ruled from the ancient Temple of Akadar. The two became divided over the love for a woman, an empathic metamorph, named Garuth. They both loved Garuth with such passion that the Kriosian empire fell. Krios eventually kidnapped Garuth from their homeworld and took her to the planet that became his namesake. This action started a war between the two worlds that lasted several centuries. (TNG: "The Perfect Mate")