The Lightning Force heralds from Earth-597, a reality where Nazi's won World War II and took over the etire world.
After a mysterious train appears in the London Train Station, shock and awe is dealt to all involved. Inside, the train is empty except for two, the Nazi Counterparts of Moira MacTaggert and Callisto. They are angry and confused at where they had ended up. It turns out that the train had been swapped with one from Earth-616. The Lightning Force then travel through to the alternate world of 616 to recover the train and Moira. They are met by the Earth-616 Excalibur and fighting is carried out. Eventually all is resolved and they return to to the own world.
The Lightning Force was created by the same creative team as Excalibur (the book in which they debuted in.) This included Alan Davis, Chris Claremont and Paul Neary.
Much the same as the 616 Captain. He is the leader of the Lightning Force. We also see him stronger for a certain period while Captain Britain is having trouble with his powers. He, also like his 616 counterpart is in a relationship with Meggan.
Nearly exactly the same, they match each other very well, with powers at the same level and personalities similar, except with the Nazi version undoubtedly ruder.
This version of Nightcrawler was much stronger than the original, being able to teleport repeatedly within small amounts of time, unlike his 616 counterpart who, at the time, had trouble doing it more than once a day. Their personalities were also similar, but with the Nazi Nightcrawler being misogynistic and arrogant.
This version of Kitty Pryde was very troubled. Being Jewish in world 616, she was also in the Nazi controlled Earth-597. She had been captured, and been used by the Nazis as an enslaved teammate. Most likely tortured, it was lightly uncovered that she had turned into some sort of Demon. Similar to Earth-616's powers effecting machinery, this version would effect the Human body, more specifically, the soul.
In this alternate team we see no incarnation of Phoenix, for no apparent reason. Speculation may include that she was never freed from captivity.
Major Story Arcs
After the Lightning Force had entered Earth-616, they attempted to free their version of Callisto and Moira MacTaggert. In doing so, they began fighting Excalibur. The Lightning Force nearly won as well, but eventually they returned to their homeworld.
In Earth-616 the Lightning Force is known as the British Superhero group name Excalibur. Earth-616 is the main and most prominent world in the Marvel Multiverse, housing majority of the charactres and storylines. In Earth-616, Excalibur is in a much different light. Nazi's haven;t taken control over the world, and everything is in a much different light. The Lightnig Force end up fighting their Earth-616 counterparts, and nearly win.