Lord of Lords Ryu Knight (TV Series)

Taikei Ryū Knight tells the story of Adeu, a boy who lives his life by the "Ethos of Chivalry" (a code of conduct similar to the Knightly Virtues), who is on a quest to Earth's Blade, a gigantic sword reaching to the sky from the ground. Along the way, he meets Paffy, who is a princess and her two escorts, Sarutobi, a ninja, and Izumi, a priest. Throughout their adventure, they come across many villains, mostly composed of thieves and bandits who are after their Ryu mechs, which are far stronger than the normal mechs.