Other than the first image everyone with birthmarks are old drawings. They are from my comic The Birthmarks of the Dark World.
A bit big pic, Dark-Fire's birthmark is pretty light but its on his neck on the right in the shape of a flame. He hides it with his scarf.

Hana/Hope 's birthmark is darker in the shape of a flower. She hides it with a glove usually

Noise's birthmark is in the shape of a music note, on her face. She usually hides it with make-up.

This is a spoiler but Harmony's birthmark is on the inside of his hands but is close to his skin color so its easy to hide.
The scar's drawing is only a year old. From The Magical Gun-Scythe. It is in the works.

Keina's neck scars are older but they still hurt. Where the scars came from are spoilers