User blog comment:Tommy,Klaus&Kol2012+/ive never been so dissapointed by a story arc in SPN until now/@comment-10889355-20190413064524

What you need to do is tone down your expectations and be realistic. The writers didn’t just decide that Jack will become a villain at the last minute. This was so obvious the moment they found out that Lucifer will have a child in Season 12. They just needed people to connect with Jack before they do so because he’s a main character. That’s how things work.

And besides, he’s a Winchester and a Winchester will inevitably go bad at some point. Sam, Dean, Cas and Mary went bad. Now, it’s his time.