Muska

Colonel Muska is a government special agent. He holds Sheeta in custody at the beginning and pursues her during the film with the military.

Muska has light brown hair and hazel eyes. He wears tinted glasses, a brown suit, a white shirt, and a pale yellow cravat. He is armed with what seems to be a Webley Mk VI revolver.

Muska is cold, calculating and duplicitous, and will turn on his allies once he has used them to attain his goals.

(Source: Ghibli Wiki, edited)