CHRONOLOGY
About 2000 years after she traded places with Excalibur’s Captain Britain, Rachel Summers emerged from the timestream. She found herself in a world ruled by Apocalypse, with mutants being the ruling class and humans the mistreated underlings. Hearing that Apocalypse was about to bond to a new host body, Rachel planed to assassinate him in this weakened state. On the way to his citadel she befriended a young Blaquesmith. Once at his lab, Rachel found the sarcophagus empty. Naturally the real location of Apocalypse was kept secret and instead, Rachel had to fight against High Councilor Diamanda, whom Apocalypse left in charge in his absence. She barely escaped and realized that if she wanted to make a change, she needed help. [X-Men : Phoenix #1]
In the following months, Rachel recruited some superpowered beings under the name Askani, the native word for “outsiders“. Also she helped a woman whom she met while being trapped in the timestream. Tanya Trask, born in the 20th century, had the mutant power to phase out of synch with time. However she could not control it, and got trapped in the timestream for years; the long isolation nearly drove her mad. Rachel was able to pull her “to shore“ in this future world.
Once Tanya attempted to go back in time to prevent her father Bolivar Trask from ever creating the Sentinels, yet Rachel used the Phoenix Force to follow. She knew first hand that tampering with the past is a dangerous thing to do, and talked Tanya out of it. Rachel telepathically erases all knowledge of their meeting from Bolivar’s mind, and two women returned to the Askani Timeline. [Uncanny X-Men #minus 1]
Rachel’s Askani gained more followers and they destroyed Apocalypse’s main power plant. Soon Diamanda Nero was so annoyed by them that she lured the Askani into a trap. Her unsuspecting Prelates Ch’vayre and Luminesca kept the Askani busy long enough for a disease carrying mutant named Plague to kill everyone in the entire area. Despite fearing that it woke Apocalypse, Rachel unleashed the Phoenix Force to purge Plague’s disease. She died and was reborn like a true Phoenix. She sent Ch’vayre back to Nero with a warning, unaware that the villainess had captured her newfound ally Diogenes Chang in the meantime.
Diamanda tortured Diogenes and gained the location of his Order of Witnesses. The Askani came too late to stop her from slaughtering the whole Order, they could only rescue Diogenes and a group of children. It was another trap as suddenly Nero and her forces attacked. Rachel sent the others to get the survivors to safety while she herself battled the villainess, who used power after power and seemed unbeatable. Finally Rachel handed over the Phoenix Force, but Diamanda couldn’t control it, and admitted defeat if only Rachel removed the Force again. She did, sending it back to the cosmos, and additionally it left Nero powerless. Rachel gained more followers each day and they started calling her Mother Askani. [X-Men : Phoenix #2-3]
In the following sixty to eighty years, the Askani movement grew and Rachel started teaching those with psionic powers. Among her pupils were both Blaquesmith and Sanctity. In time a full Sisterhood was established and they set up various colonies, much to the anger of Apocalypse. Rachel continued to preach about the so called Askani’Son, who one day would liberate this future world from Apocalypse. For years she searched for a way to transport her baby brother through time, well aware that he would grow up to fill that role. Also Rachel used her power to let her consciousness flow through time various times. She revealed the identities of the fabled Twelve to Cable for example. [Cable (1st series) #65]
Apocalypse caused distortion in the timestream, making it next to impossible for bodies to time-travel, however one woman simply called Askani volunteers. She has a natural mutant talent for time-flying and backed up by technology she embarks on the journey. She discorporates, makes the transit in a state of pure energy, but on arrival the reintegration fails, and Askani survives only as a sentient energy being, held together by sheer strength of will. Askani knew that she would not survive for long, but at least she accomplished her mission. She followed X-Factor to the moon where Apocalypse had taken baby Nathan Christopher and infected him with a techno-organic virus. In the 20th century Cyclops‘ son had no chance of surviving the infection, so Askani took him with her to the future. It was a permanent goodbye, as only Askani was the only one able to make the trip at all, and her energy form would soon dissolve. [X-Factor #66-68]
Back in the future the baby was investigated, and Boak, who had overseen the time travel found it’s lifesigns fading. He informed Mother Askani, who then gave the order to clone the child as a precaution, should it really die. Her decision somewhat shocked her Askani followers, as actually cloning and genetic tampering was the way of Apocalypse, but Rachel repeated her order and did not allow anybody to question her authority on the subject.
The operation was successful, with the clone only showing a few scars instead of the template’s metallic body parts. Surprisingly the infected child too survived, with the techno-organic virus no longer spreading. Before Mother Askani and her followers could think about what to make of two Chosen Ones, their stronghold was attacked by Apocalypse’s Canaanite troops. Rachel was mortally injured and Boak managed to rescue only the real baby, while the clone fell into Apocalypse’s hands, who named it Stryfe. [Cable (1st series) #7-8]
Having recovered from her wounds, the Bright Lady (another alias for Rachel) knew that she would need to warn the X-Men about Stryfe not being dead after the events of the X-Cutioner’s Song (check the Askani – present entry), and another operative of the sisterhood was chosen. She too dubbed herself “Askani“ and knew that her journey would be a final one, as her predecessor had already proved. She ventured back in time, too became an energy construct in the process and managed to alert Jean Grey, before being captured and being killed by Stryfe.[Cable (1st series) #6-8]
Being over hundred years old, Rachel knew that she would not live long enough to raise and train young Nathan herself, especially since Apocalypse’s forces defeated more and more colonies of her Askani. Having prepared special host bodies, she transported the consciousnesses the minds of Jean and Scott through the centuries. Right after filling them in on their task, she was injured by Paladin Ch’vayre and fell into a coma.
Using the alias of Slym and Redd Dayspring, Jean and Scott spent twelve years in the future, during which they raised young Nathan and helped him use his powers to keep the techno-organic virus in check. They also joined Clan Rebellion, a terrorist group opposing Apocalypse’s rule, and found data on the Legacy Virus, still in testing phases, while raiding one of his stronghold’s laboratories. Hitting puberty, Nathan’s techno-organic virus flared up, and he was on the brink of dying, but Rachel mentally guided Nathan into telekinetically pushing back the virus.
In all these years, Apocalypse had been training Stryfe in his abilities, wanting to use him as his ultimate host body, that won’t burn out from containing his vast energies. After serving Apocalypse nearly a whole century, Ch’vayre finally understood that Apocalypse’s view of the world was wrong. He tried to talk his master out of bonding to the boy but failed. During the process Apocalypse discovered that Stryfe was merely a clone and would actually not be able to contain his vast energy. He got very angry, and right then Redd, Slym and Nathan attacked. Separated from any useful host, Apocalypse finally perished. 
The Mother Askani too died of old age, and the minds of Jean and Scott returned to the present after saying goodbye to Nathan, who now had to fight without them to restore Xavier’s dream in the ruins of Apocalypse’s world. [Adventures of Cyclops and Phoenix #1-4]