Manga Parallels (icky warning ahead)

[Exrael]

One of the peculiar things I've picked up from reading thousands of manga is the existence of uncanny similarities between random series. The only ones I have saved are from horror manga, strangely enough, but they are still oddly specific and alike.

Fingernail in the roof water tank
Apocalypse no Toride:

Kouishou Rajio:

Corpse thing made of many faces
Higanjima:

Green Worldz:

Berserk:

Mountain of bodies to reach a castle
Berserk:

Vinland Saga:

Have y'all ever found any cool/strange parallels between manga series? :'3

[IucieI]

i don't usually look for parallels in manga, but i do know that there's something like a mountain of bodies in the series no.6 too :0

[Operadaisuki26]

Culture
and
Moe

And about parallels, think of the old disney formula for princess films, everyone liked'em then Disney company tries to do original stuff and the quality of the films lowers. But then the tried and true Disney formula was used in Frozen and then voila its popular again. So patterns are repeated to create an audience.
It's not parallels its just techniques or urban legends or popular ideas that get reused.