Loving A Mass Murderer And My Best Friend (Frisk x Chara x Asriel)
Everyone is born with a black smudge on the inside of their wrist. Every birthday, the smudge starts to disappear; until finally on their 16th birthday, the smudge completely disappears to reveal the name of their soulmate. Frisk lives a normal high school life, the only difference between them and their school mates...