As Heaven and Hell continue to use Earth as their new battleground, Abaddon entertaining grand plans for conquest on Supernatural.

The Knight of Hell (Alaina Huffman) made her debut last season during "As Time Goes By," and introduced viewers to a new form a demon. While the Winchester brothers (Jared Padalecki and Jensen Ackles) had difficulty figuring out how to off their new problem child, the hunters finally managed to shoot a devil's trap bullet into her skull and bury her in concrete.

However, when they were trying to figure out how to cure demons, Dean (Ackles) dredged Abaddon back up. Unfortunately she pulled a disappearing act and is now busy creating stronger, more militant demons in preparation for her takeover as the new leader of hell.

Adam Glass, the writer who first created the Supernatural character, recently discussed how the idea for Abaddon came to fruition.

"I knew I wanted to write a Femme Fatal character," Glass tweeted on Tuesday. "I just needed a story for her and a why."

Although Glass didn't pen the script for "Devil May Care," the episode was in the hands of fellow writer Andrew Dabb.

"When [Andrew Dabb] and I started talking about Men Of Letters and Henry we needed a new big bad. But Crowley was so great. Couldn't top him," Glass wrote. "So, why not go another way. Woman. Bad ass. Something more then a demon. Research revealed Knights of Hell. And in it I saw the name Abaddon."

When he was first writing the character, Glass modeled her after actress Lauren Bacall. During auditions, Alaina Huffman managed to blow the writers away.

"Then [Alaina Huffman] came in and read and I...almost jumped out of my seat," Glass explained. "She was perfect. [Executive producers] Jeremy [Carver], Bob [Singer] and I all agreed instantly that she was Abaddon."

Catch Abaddon as the new big bad on Supernatural which airs Tuesdays at 9 p.m. ET on the CW.