Romeo

ロミオ

Romeo arrives from another planet as a servant robot for his alien master, but his clumsiness causes his master to crash into another UFO and subsequently enter a collision course with Earth. Since then, Romeo and his master have been stranded in the South Pole for a millennium until he is ordered to find assistance to free the mothership. It becomes fortunate that Romeo finds Kuro and his friends, who help foil his master's invasion attempts over and over again. However, simultaneously, Romeo suffers on the wrong end of the stick from Kuro's wrath or karma itself for any trouble he may intentionally cause or not.
Despite being both a blessing and a curse for sticking around with Kuro and company, Romeo eventually finds his long-lost love, Juliet. They eventually marry during the latter half of both the manga and anime, and gain many children.
Although Romeo manages to settle down on Earth with Juliet by his side, he still dreams of returning to his home planet. But his attempts eventually fail due to a bad stroke of luck or mainly Kuro's shenanigans.