Rachel's History (pay close attention now, she IS a Summers after all ;)

Rachel was born into a world where Scott and Jean had married much earlier than in mainstream Marvel. Everything seemed to go wrong; Jean was killed in an explosion in Pittsburgh, due to Mastermind.

Nine years later, many of the X-Men, including Prof.X, were
massacred on mansion property. Rachel was taken by the goverment, and given vertical facial tatoos which mark her as a hound. Ahab, the hounds master, turned her into one of the mutant hunting hounds, who track down and subdue mutants for the goverment to kill later. Rachel was the best there was.

Years afterward, Rachel was no longer neccesary, so the goverment placed her into the South Bronx internment camp, where she met the remaining X-Men.

Rachel sent Kate Rasputin's (Kitty Pryde or Shadowcat to you or me) consciousness into the past to prevent the assasination of Sen.Kelly, whose death had caused those horrible avents to occur. Then the remaining X-Men broke free of the camp, fleeing into the Morlock tunnels. The Sentinels tracked them down and killed Rachel's love, Franklin Richards (son of the Fantastic 4's Sue and Reed). In retaliation, Rachel destroyed the Sentnels.

They fled to the Baxter Building, former HQ of Franklin's parents, where Colossus, Wolverine, and Storm died. Only she and Kate Rasputin were left, and they planned to destroy the deadliest Sentinel, Nimrod.

To get by security, Kate used the password "Carol Danvers", then, knowing she was trapped by the phase-proof walls, said "Dark Phoenix", which teleported Rachel to the mainstream Marvel timestream. Kate was then killed by Nimrod.

Rachel had, unbeknowst to her, been transported twenty years into the past. She knocked on the door of the X-Mansion, only to be greeted by a teenage Ilyana Rasputin! Rachel was shocked, as the Illyana of her time would not be 15 for eight years! Rachel fled to NYC, where she was attacked by the villainous Selene. Rachel fought her off, and hid in a nightclub. There she met a young man named Nick, who took her to his house. While Rachel bathed, Nick made them dinner. Rachel lost her mind-link to Nick, and ran into the kitchen only to find Nick disintegrated to ashes!

Selene attacked Rachel again, until the X-Men appeared and drove off Selene.

Rachel was not delighted, to say the least, when she found out her mother was dead and her father was married to another woman (Maddy Pryor, incidentally). She nearly killed Nightcrawler in her fury. She joined the team, taking the name Phoenix 2, and made everyone promise not to tell Scott Summers who she was.

While the X-Men were battling Freedom Force in Washington, D.C., she snuck into her grandparents house. She touched a crystal ball that contained the essence of the Phoenix and absorbed it. Deciding to put her power to good use, Rachel fought the Beyonder -- and nearly destroyed the universe!

Later, to avenge Nick's death, Rachel infiltrated the Hellfire Club and battled Selene. She nearly killed her, but Wolverine stabbed her through the gut with his adamantium claws (hairy lil' runt, grrrr...). Ray got back by flinging him in front of a train later. :)

Spiral tricked her into the Body Shoppe, and trapped her on Mojoworld. Ray escaped, and the people who would eventually become Excalibur (Meggan, Capt.Britain, Shadowcat, and Nightcrawler) rescued her. They joined together, took up residence on Braddock Manor, and became Excalibur.

Meantime, Jean Grey comes back to life, Maddy Pryor discovers she's a clone of Jean, she goes crazy, becomes the Goblyn Queen, and eventually dies. Jean and Scott decide to raise baby Nathan, Maddy and Scott's son, together.

Rachel attended her parents wedding, then was given the choice to stay in 616 time, or trade places with Brian Braddock (who was trapped in the timestream). She chose to save him, and was hurled into the 40th century and starts the Askani. Later in her life, she comes back to get her little bro Nathan, who's dying of a nasty Techno-Organic virus. She takes him back to the 40th century with her, where he is cloned.

Nathan becomes, of course, Cable; his clone becomes the evil, demented Stryfe. Rachel loses the Phoenix Force and later dies :(

The current writer of Cable has confirmed that Cable's future no longer exists; therefore Rachel may yet return, either in her adult state -- or as a baby, to be born to Scott and Jean.