Movie based on the 1996 TV anime with an original plot.

It is the year 1995. Earth has been conquered by an alien army from the Saar cluster known as the Akron. The cities of Earth have been destroyed, and the remaining survivors live in harsh shanty towns and villages. Kento, a war orphan, hides within a cave along with his companions in order to escape some bandits. In the cave, they find the secret base of Dr. Earl, who was an inhabitant of the planet Helios, a planet conquered by the Akron. Dr. Earl then fled to Earth, bringing with him the greatest achievement in Helian technology: the super robot Daltanius, whose power is increased when combined with the intelligent lion robot, Beralios. Dr. Earl entrusts the fight for Earth to Kenta, who happens to be a descendant from the long disappeared Helian royal line. (Source: Wikipedia)

Failed kamikaze pilot Ken Asuka becomes a rough, tough hooligan who settles all of his problems with karate, until he learns about the legendary swordsman Musashi Miyamoto in the novels of Eiji Yoshikawa. Resolving to live his life like Musashi, he begins to take karate more seriously. Based on a manga by Ikki Kajiwara and Jiro Tsunoda, itself inspired by the real life of Yasunobu Oyama, the founder of the "hard-knock" Kyokushin Karate school.

The Kodomo No Omocha OVA is a thirty-minute animation video that was made before the TV series. It covers the first volume of the manga, so it's equivalent to TV episodes 1-6. It relates Sana's troubles with Hayama at school as a result of the "oyakodon baka" situation and culminates when Hayama's dad and sister realize their mistakes thanks to Sana's efforts.