- Episode 9 featured a Battle Beast named Cleo who had a human form and sent by Archduke Gorgon to infiltrate and destroy the Fortress of Science via a bomb planted on her. Thing is, Cleo became very conflicted since she already enjoyed being a human and constantly begged for Archduke Gorgon to not turn her into a Battle Beast and she even contemplated suicide where she couldn't harm anyone. And Archduke Gorgon would never let her have her way. Shiro, Boss and Jun eventually found out about this and actually didn't want her to die, and managed to stop Tetsuya from dealing the fatal blow. And that was the time finally Gorgon pulled the trigger and blew the bomb right in front of Tetsuya and friends. After previous episodes ended happily, this one ended sadly as Tetsuya buried Cleo in the sea, with him and his friends in tears, and especially when Tetsuya regretted that he could've saved her from her cruel fate if only he knew about her good nature earlier.
- In one of the final episodes, Sayaka wants go to fight, but Professor Yumi tries talking her out of it, reasoning Diana A is too weak to fight, and he does not want jeopardizing his daughter's life. Professor Yumi had been a somewhat distant father throughout Mazinger Z and Great Mazinger, but every so often he showed he truly cared for his daughter. This was one of those times.
- Professor Kabuto begs Kouji as he is dying to treat Tetsuya like his brother. Instead of asking him why he is leaving him AGAIN, Kouji vows to do so.
- After Professor Kabuto's death, Tetsuya is berating himself, thinking it's all my fault (he is right), and he vows he will never again feel petty jealousy as Jun watches over him.
Tear Jerker / Great Mazinger