Here's a beautiful rendering of Charlton's Nightshade by Will Meugniot, an artist better known in the animation world, but respected by me for his outstanding Good Girl work on Femforce and his great run on DNAgents with Mark Evanier so many moons ago.
Nightshade was the sole female "Action Hero", appearing first as an enigmatic partner and at times seeming love interest for Captain Atom. She appeared in several Captain Atom adventures and was first drawn and presumably desgined by Steve Ditko.
Eventually she was given her own feature in the back pages of Captain Atom, with a story by David Kaler (her co-creator) and artwork by Jim Aparo.
To get a good look at one of these handsome tales check out this link. Nightshade takes on Jewelee, a villainess she first encountered with Captain Atom, and we meet her trainer, a man who will be familiar to Judomaster fans.