Mazinger Z vs. Devilman

Mazinger Z vs. Devilman , Majing Zetto tai Debiruman? is a 1973 animated movie that crossed over two thenpopular Anime series, both of which were created by Manga artist Go Nagai. Note however that the movie features alternate versions of events from both series, and is therefore not canonical to either one.

The combined forces of Dr. Hell and the demons then attack the Laboratory Devilman flies to help defend it, but is overwhelmed and captured. Hes taken to some obviously magical clouds, where hes placed on an ice cross and tortured by the demons for being a traitor. However, as soon as the Scrambler is repaired, Koji uses it to fly the Mazinger into the clouds, killing the demons, freeing Devilman and finally destroying the flying fortress, although Hell and Ashura escape alive.

Source: Wikipedia