What are these rhombus/triangles around the neck?

Question

I saw these rhombus/triangles around the neck in a few stories but do not know what it is:

• I'm Not the Evil God's Lackey character - Original Witch Silver

  

• I'm the Grim Reaper (webtoon) character - Satan

  

What are these?

Answer 1

For the first character, it appears to be a geometric choker, while on the second character, I'm willing to bet it's a scar going around their neck. I've seen scars depicted as beveled diamonds in a row like that, and there are other anime characters with similar scarring which the artist likely took inspiration from, but these are just my initial musings upon skimming stories and looking at character designs, I could be completely off.