Desler is the Leader of the alien race known as the Gamilas and the main villain of Space Battleship Yamato. It was Desler who masterminded the attack on Earth, forcing the humans to move underground due to the radioactive meteore-bombs unleashed on the planet by the Gamilas fleet. Although initially portrayed as a dictator bent on conquest seemingly for it's own sake, it's later revealed that Desler seeks to conquer the Earth in order to find a new home for his people, following the imminent destruction of their home-planet.

(Source: starblazers.com)