(10) He falls by stages to the Dark Side, from pride to fear to anger to hatred. After ten years of careful orchestration, his personality is broken and twisted almost beyond recognition; his Anakin-self, Anakin-that-was, becomes a distant memory, surviving only in the battered, tenuous attachments to the people Anakin loved. His wife, his unborn child, his mother's memory; none of these keep him from evil, but in the end, they keep him from worse evil.
(9) He doesn't realise this until years later, when Vader is nothing more than a memory of madness; and he also realises that the Emperor must have seen it from the beginning, and planned accordingly. Sith prize attachments about as highly as Jedi do.
(8) When Vader sets a spy on his wife, it's not because he doubts her; the spy may not know the child is his, almost nobody knows the child is his, but he does. He does it to protect her; it's for her sake. Everything is for her sake.
(7) Vader is busy enslaving himself to the Emperor when Padmé goes into labour, weeks earlier than expected; too early for anybody's schemes to proceed smoothly. It is his spy who overhears the half-formed plan to hide the baby from Vader, when it's born -- his spy who steals Luke before Palpatine or Obi-Wan can get their hands on him, and his spy who overlooks the other child.
Padmé, thank the stars, never knows. She dies before Luke goes missing.
(6) At the hospital, Vader's rage blunts Anakin's grief.
"The child came early," he says, very quietly. "Is that why she is dead?"
"No, my lord. She seems to have suffered a -- a heart attack."
"A heart attack," repeats Vader, and from the morass of emotions he feels, one clearly emerges: bewilderment. "Is that customary for one of . . . Senator Amidala's age?"
"Of course not!" The doctor feels a strange tightness in his throat. "If I didn't know better, I'd think she'd been electrocuted."
Vader's red-gold eyes drop to Padmé's corpse, settle on the face twisted in anguish. Force-lightning, he thinks distantly, and releases his own grip on the Force.
The doctor never knows how slender a thread his life hung upon.
(5) After the years of falling, it takes him ten minutes to turn back: the same ten minutes it takes him to return from the hospital. His anger is subsumed in terror: Padmé is dead, just like Shmi, and not an hour ago he left Luke at the imperial palace -- it's his fault, all of it. He knows he can't defeat the Emperor; he's stronger, yes -- stronger than everybody -- but he doesn't have his master's experience, his knowledge. He couldn't save Mother or Padmé and he can't save Luke. Anything he does --
A whisper in the Force brushes past his mind, and for the first time in months (years?), he listens. It says:
Palpatine has never been a Jedi.
Never been a Jedi. He repeats the thought stupidly, before realisation crashes in on him. Palpatine has never been a Jedi. He's never trained in the Light Side, never studied it, never known it --
Calm settles around him, like a comforting blanket, and Anakin's eyes fly open, wide and blue. It's his only chance.
(4) He is still calm when Palpatine's body falls at his feet. So this is the end of the Sith: an old man and a young father. It seems fitting, somehow.
(3) Anakin knows that the Emperor possessed every last shred of data about the Sith, every possible way to follow that path. Now the information exists only in two places: Anakin’s head, and the Emperor's library.
Cradling his son in his arms, he delivers Darth Vader's last command: evacuate the palace.
Then he lights it on fire.
(2) After that day, he never again touches the Dark Side. He doesn't dare, not with Luke depending on him, looking up to him, and really, he doesn't much want to. He knows, better than any of the masters harping on old dogma, that it controls you, twists you until you aren't yourself, until your own mother doesn't recognise you; that it's as much madness as evil.
A madness freely chosen, however, so he does not allow this to assuage his conscience.
(1) Anakin quietly raises his son on obscure Outer Rim planets. They even spend a few years on Tatooine, not far from Shmi Skywalker's grave.
Luke doesn't mind; he's inherited more from him than midi-chlorians, and they're happy to wander the stars together. Besides, Anakin is determined to train Luke himself, away from the weight of their name, away from the restored Republic, away from those who would rip them apart and warn his son against attachment.
"Father, Father!" cries Luke, waving a hydrospanner. "I did it just like you told me and he started talking again! Can we go now?"
Anakin examines the child's handiwork and smiles. He does not pretend that he is a good man, not after everything he's done, but perhaps he is a good father.