The Power Stone has the power to grant the wielder access to all power that has ever existed or ever will exist. As with any of the stones, the power increases with the physical or intellectual capabilities of its holder. The Stone grants the user unlimited strength and durability making the most masterful wielder to become virtually invincible. While being able to be used as an unlimited power source for any machine it can also be used to back up the other stones and amplify their powers.
In the comic books it was originally created when Nemesis destroyed itself; the Elders of the Universe bound all the Stones together to defeat Galactus. When the Elders ultimately fell, the Power Stone then resided with The Stranger. Yet Thanos inevitably obtained all the stones, as well as the Gauntlet, and the ensuing Infinity Wars began.
In the Marvel Cinematic Universe(MCU) the Power Stone was created from one of the 6 singularities that predated our universe. The Power Stone is referred to as The Orb in the MCU and is introduced in the film Guardians of the Galaxy. The Cosmic Beings attempting to contain the Power Stone, linked themselves together but were inevitably destroyed by the raw energy contained in the stone. Millennia later, the Celestial by the name of Eson the Searcher used the stone to place judgement on planets he deemed unfit. Using the energy contained in the stone, Eson destroyed entire planets in the blink of an eye. The Power Stone being unstable, eventually over-rode the Celestials control and destroyed him. Due to it’s inability to be controlled, it was contained in The Orb and placed in a hidden vault on the planet of Morag. Thanos, on his quest to obtain all the Infinity Stones, discovered the location of the Power Stone on Morag and dispatched Korath the Pursuer to steal it. As Korath entered the chamber he found Peter Quill(Starlord) had arrived only moments before and removed The Orb from its holding cell. Starlord escaped with The Orb, and with the help of the other Guardians of the Galaxy, made his way to The Collector in Knowhere where we finally get the first glimpse of the true history of the Infinity Stones in the MCU. Ronan the Accuser stole the Power Stone from Starlord and, double crossing Thanos, imbues himself with the Power Stone in an attempt to annihilate Xandar, the capital planet of the Nova Corps. Ronan was destroyed in the end, when the Guardians of the Galaxy were able to utilize the Power Stone as a group, and channel its energy at him. With Ronan destroyed, and the Kree threat neutralized, Starlord entrusted the Power Stone with the Nova Corps, and it remains there to this day.
The future of the Power Stone is interesting in that Thanos clearly needs to completely destroy the Nova Corps in order to obtain it. What this provides us with is the precedent in which the Guardians of the Galaxy are going to need to go toe to toe with Thanos in an upcoming film. Since the Nova Corps have the Power Stone, it is entirely possible that they will use it to power their defenses from this point forward. When Thanos arrives looking for the stone, he may, in one fell swoop, demolish their entire force simply by stealing the Stone. All we know for certain is Thanos is coming for that stone and will stop at nothing to obtain it.
***As the MCU progresses this page will be updated***