Heya hi! So, this is Teresa Parker! Long lost Parker sibling and likely future SHIELD agent. She's got bioluminescence powers (yuuuup she glows) but can use the ability as an energy source (we're talking photon guns and photon wings/jetpacks and such). She's got the codename Firefly and she's got her mother's looks and temper. The whole bulk of the starting point for when she's taken is a mission to take down Nick Fury that ends with her turning on her teammates and working with Nick/getting tied to Peter and @MAY PARKER to protect them from the revenge that'll likely come with her betrayal. There's plenty of more details that I'd be more than happy to work out/brainstorm with the taker and I think there's plenty of fun to be had with a woman in her 20s who is socially inept and her way too talkative dorky teenage brother. He could teach her to quip and show her hot dogs and she can show him how to break someone's ribs in three moves :|. Plus there's an empty seat at the Parker family table that could use a long lost sister/niece.
FC is Shelley Hennig/open. She's the result of a search I did for someone who fit the concept but if you got someone else who fits please do suggest them!