I'm excited to see Sigourney explore her dark side! These are my 4 picks, who would you choose?

Lilith, Mother of Demons is an ancient demonic goddess with immense power and connections to Dr. Strange. It would be an unlikely turn of events to have our hand-to-hand heroes face a supernatural foe, but finding a way to work as a team to defeat such insurmountable odds could also strengthen the series.

Headhunter is ruthless and cunning. She's calculated, methodical and mysterious...a lot of great material for SW to work with. Her power is a repeat of Purple Man's mind control from Jessica Jones, but her abilities are more refined and she has a tight team of operatives at her command.

Madame Masque has family ties to the Maggia and is more deeply rooted in Iron Man's lore, but the gold mask is pretty striking and she could be a continuation of dealing in death with advanced weaponry, possibly even stolen Stark tech.

Sin is the daughter of Red Skull, eventually jacking up her head to look like ol' pa. I don't know much about her and the likelihood is pretty low, but tying into Cap's storyline would be pretty cool.