The Mark of Cain page is flawed and has noticeable errors. Here are some changes that I am suggesting:
1. Split the page into two, one for Dean’s and one for Amara’s. They aren’t really a single marks. They are like twins and if one is destroyed the seal is broken.
2. Change the info box. It’s not an item. It(or they) is a Sentient being. This should be obvious.
3. Add it to the primordial entities page. It(or they) is a sentient entity(or entities) that existed before the creation of the universe.