ZacZimCon

It's true that in the majority of cases, crucifixion in Japanese cartoons isn't meant to be conveying any specific theological message, but something Western audiences are likely to miss is that a large portion of those random crucifixion scenes are referencing Ultraman.

Ultraman's creator was a devout Roman Catholic who explicitly intended the titular hero to read as a Christ figure, and consequently, various Ultramen have been crucified on multiple unconnected occasions throughout the franchise's history. Crucifixion scenes in Japanese cartoons are often directly name-checking particular crucifixion incidents from Ultraman, right down to emulating the compositions and camera angles of specific shots. It's like an especially morbid version of the Akira slide.

The upshot is that, while it's true that the inclusion of gratuitous crucifixion scenes in Japanese cartoons typically has no (intentional) theological message, stating that they have no cultural significance is incorrect. A large chunk of the Japanese viewing audience are going to see them and immediately go "hey, that's an Ultraman reference".

Anyway, as an image tax, have a shot of four crucified Ultramen miraculously resurrecting a fifth Ultraman by shooting laser beams out of their hearts:

“She’s the last unicorn in the world.” “It would be the last unicorn in the world that came to Molly Grue.”