These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Moral Event Horizon: One episode has Doldora using her Monster of the Week to create an illusion of the Fivemen's mother in order to set a trap. Seeing the way Remi holds onto the hope that her mother might be real is enough to send Doldora over.
Billion gets a sword that makes its user Brainwashed and Crazy, as well as giving them evil powers. He gets one of Gaku's kendo students to use it, preying on the fact that the kid wants to be stronger in order to protect his parents because he knows the Fivemen won't kill the kid.
Then we have Galois, after destroying the Fivemen's Humongous Mecha, but not the Fivemen themselves, he decides to draw them out, by attacking their school full of children. The scene with the children running to escape like they're about to die cements it. Shortly before these happens, he has dropped his Butt Monkey status, if you didn't notice.