"You were my brother, Anakin! I loved you!"
A trained Force user can nearly always hear a lie when it is told. An enraged Sith in the middle of the memory he would use to access the Dark Side for most of the rest of his life could not possibly miss one told by the object of his rage, the cause of his agony. This does not mean that he knew what the lie was.
Caught in a trap started by the Emperor and finished by his own hands, hardly able to see through the fact that even his eyelashes were on fire, Darth Vader heard the lie in that statement. In the bleeding, burning remains of the heart of a boy who used to go to his master when he had a nightmare, of a man who would have died for him without hesitation only yesterday, it seemed entirely obvious that the lies were 'brother' and 'love'. That the Obi-Wan he had known most of his life, still half thought could fix everything if he could only make him see reason – that that man had never really existed. Never actually thought of him as anything but a tool to be used, controlled with the appearance of affection, and cast aside when he became inconvenient.
Those words, of course, were not the lie.
Obi-Wan Kenobi loves Anakin Skywalker with every speck of who he was. If the parts of his identity were peeled away one by one, that love would be the last to go. When he did not value his life over a lightsaber to the ribs, hadn't used his own name in nearly twenty years, and the centre of that love was the one swinging the lightsaber, it still hadn't. When there was not even a body left of Obi-Wan, the love – however ignored, however twisted through metaphors and points of view – had not dimmed. He simply thought it should have.
Obi-Wan had never had a brother, in the sense of blood or law. He technically had a sister – had even met her, once, on a mission to her home moon during the Clone Wars – but Kenobi was a common enough surname on Pilare and she was hostile enough toward Jedi that he'd never really been sure of that. Anakin only technically had a sibling as well, considering that meeting his mother's stepson one time didn't exactly constitute a brotherly relationship. There was not much aside from other people's descriptions to him of their relationships with their siblings for Obi-Wan to base his description of his with Anakin off.
It was enough.
He had seen Anakin grow up – run after the nine-year-old, completely unable to handle the sugar rush of the first refined-sucrose dessert he'd ever had; rolled his eyes right back at the snarky sixteen-year old; sat up at two in the morning helping the stressed twenty-year-old study for his Trials; assured the disillusioned twenty-two-year-old he'd be a Master at some point. They'd laughed together and yelled together, laughed at each other and yelled at each other. He could not imagine a version of his life that didn't have Anakin in it and was terrified at the realisation that he'd have to live it.
The lie was not 'brother'. It was not 'love'. It was 'were' and it was 'loved'.
AN: Very unpolished oneshot, really more about how I interpret these characters than any sort of plot considerations. The mentions of stuff that isn't in canon aren't from any comic I've read or anything; they're elements from other fanfics I'm working on, slotted in because I felt like it.
The change in tense in paragraph five isn't a typo, it's because, what with Force ghosts, saying 'loved' there would, I feel, imply that this stopped being true for Force ghost Obi-Wan at some point or, if he eventually 'became one with the Force', the Force itself. That would go against the entire point of this. So, this all happened a long time ago in a galaxy far, far away, but the love is still there and always will be.
This is rather sloppier than I usually try to be, because I wrote it all between 8:30 and 11:41 (now) on a school day and it mostly exists because a few lines from it wouldn't leave me alone.