Undereich

Omg your back

I have mixed emotions about this

some mf flagged this saying "it promotes nazi"

I didn't flag it but I can see why
The things on their arms
They kinda have the Nazi symbol

The Swastika.

Is that what those are called?

yes, and chara and asriel are wearing them

And their a Nazi thing?

Yep, the Nazis during WW2 and present used swastikas as their symbol.

most likely this image was edited by someone to have the swastika, as the design is not centered on the armband.

This image has no context, besides the fact "reich" means realm in German.