- Sin is the daughter of Red Skull.
- Sin was first mentioned as Sinthea Shmidt in Marvel: Avengers Alliance Mission 12.3 in a deployment text.
- Sin was confirmed to appear in Season 2 Chapter 3 as a villain, according to NYCC 2013 Announcements.
- In Season 2: Chapter 6 - Mission 4, Sin first appeared in her Skadi form.
- Skadi takes 2 actions every round.
- Skadi has two themed weapons: and .