Thundra is a redheaded, female warrior from a matriarchal, technologically advanced future timeline where men have been subjugated by such women; who are known as Femizons. She was first introduced in Fantastic Four #129. Thundra's powers include: superhuman strength (she can lift approximately 60 tons) & durability, and all of her other physical attributes are heightened to the peak of human capability. During her lifetime she has received extensive combat training. Her weapon of choice is a length of chain, which is often attached to a bracelet on her left forearm.
Like previous flashback Doc Samson, Thundra has mostly been a semi-regular player in various Marvel comic books. Due to her radical feminist viewpoint, she typically takes the role of an aggressor in these rare appearances, but despite this, she has been shown to be a noble hero and simply a product of her 23rd century environment.
When Thundra first warped back in time, she temporarily joined the criminal team- The Frightful Four, but she did so for her own reasons and ultimately turned on them to assist the Fantastic Four, partly due to a romantic attraction to team member, Ben Grimm/The Thing.