Get Back the Spring of Life! I Shall Return - S1.E24

Which brings us handily to the sixth and final plot arc of the series. Team Gokudo make a beeline for the country of Yanu to find the Spring the Life, which allegedly should be able to age Gokudo back to his previous self. Of course, by the time they get there, they discover that thanks to an religious putsch by the followers of the Fire God (Ryu Gee), the Moon Goddess (Negana Luna) has been disembodied and her Spring of Life has been converted into the Spring of Fire.

Luckily for Gokudo, all that's needed is for someone to host the avatar of Negana Luna so she can reclaim the Spring, so naturally Gokudo volunteers Rubette! After some interesting comedic shenanigans, our 'hero' prevails and does get his normal body back at last... by way of a very amusing scene involving (the now-naked) Gokudo and his Magic Sword. All is not happiness and light, though; the local gods haven't settled their ongoing feud and Ryu Gee comes to vanquish Negana Luna, gobbling up Gokudo in the process.