UFO Ultramaiden Valkyrie

UFO Ultramaiden Valkyrie (円盤皇女ワるきゅーレ, Yūfō Purinsesu Warukyūre) is a science fiction/comedy anime series based on the manga series UFO Princess Valkyrie. The anime series ran for 2 seasons totaling up to 32 anime episodes and one OVA episode. The anime series was released on DVD in Japan between 2002 and 2006, and were licensed by ADV Films from 2006 to 2007.

The manga series UFO Princess Valkyrie (円盤皇女（ユーフォープリンセス）ワるきゅーレ, Enban Ōjo Valkyrie) was published in Japan by Square Enix in the magazine Monthly Shōnen Gangan beginning in 2002 and finishing up to eleven volumes in 2007. This series was created by the manga group Kaishaku, the group also known for creating Steel Angel Kurumi. The series was also published by Media Factory as four volumes under the light novel label MF Bunko J.

Plot
On a world where aliens are commonplace, Kazuto Tokino decides on his own to run his grandfather's bathhouse despite his parents' protests. Kazuto however lacks a lot of the skills needed to make such a venture successful and must get by on a sunny disposition. That alone might have made things hard enough for him, but an alien princess named Valkyrie destroys the bathhouse, and in the process mortally wounds Kazuto. However, she is able to save his life with a magical kiss, but that kiss costs her half of her soul and transforms her into an 8-year-old child, though when Valkyrie and Kazuto kiss, their souls connect allowing her to temporarily assume her adult form and wield the Key of Time, a powerful sword-shaped artifact. Princess Valkyrie is then stranded on Earth, unable to look after herself as the entire solar system is out searching for her. Over time, Kazuto and Valkyrie fall in love with each other.