Axel fights Saix. He fights Marluxia. He fights Larxene. Countless others; countless times. He goads them on until they are blinded by fabricated rage, finally willing to fight him, fight with him as if it were their last.
He doesn't have any personal qualm with the participants, quite the opposite really. It is the fight itself he is grasping for, the opponents merely vessels.
When he is in battle the adrenaline shoots through his veins. It pumps rapidly as if it were his heartbeat, burns as if real emotions, ricocheting as if thoughts. It is enough to trick him into believing he is alive, if only for that fleeting moment. The feeling is addictive, as he is grasping for it once more not long after it vacates him, sometimes lasting only hours before he is desperately searching again.
During the matches Axel will slip up on purpose; will let the respective weapon pierce his flesh, comforted by the fact that he still bleeds red. He relishes in the pain, euphoric almost in the idea that he is feeling. It is because of this that Demyx is often found in his room, patching him up. Like a lifeless rag doll.
Whether Demyx is stitching a gash or bandaging some wound, Axel tends to shift slightly, almost forcing Demyx to abruptly brush against something that will cause him pain. The blonde boy will stutter his apologies, unknowingly pretending to be deeply sorry. But Axel reassures him it's okay, as he internally sighs with the uncomfortable sting. It serves as his reminder that he exists, somehow.
But it is not long before he starts to grow immune to the pain. As soon as he realizes this, Axel is searching again for anything to keep him anchored to this world, to prove that he is more than just an empty husk. Demyx is always willing to help, always wants to help others and ease their pain. Consequently, that is his solution, his way of feeling as if he is doing more than simply existing.
And so Demyx willingly offers his services to help Axel in his quest for life. If his method aids in the method of another, then that is icing on the cake.
After hours, when they are together, something like that familiar and warm adrenaline comes to life. Sliding like electric waves through their bodies, pulsing soothingly. It is not exactly like the hammering poison from before, but it is close. It is good enough for this moment.
If Axel had a heart then he might have realized how wrong this was; using Demyx, something as close to a friend as he would ever get. He might have realized how much it could hurt Demyx. But he didn't have one, and neither did Demyx, so the thoughts never crossed their minds.
But as all things do, it fades as well. The sensations dull and the novelty wanes. All too soon he is off again, searching for his salvation.
Roxas joined around the same time. The vacant boy caught Axel's immediate attention. Yet what he failed to notice was that he caught everyone's attention.
He sought out the newest member, drawn to him in ways he could not even begin to fathom. Zexion said it was because his somebody was still alive, and so he still carried a ghost of human emotion in him. The emotion that flickers frequently and sometimes flares to the surface for a moment. And it stirs remnant memories in the other nobodies.
But Axel doesn't care the reason, he doesn't care what fancy words the cloaked schemer uses to try and rationalize the situation; all he cares about is how Roxas can make him feel. It is better than he could have ever imagined, better than anything he could have fabricated. It is only a small fraction of what real people feel, but to him it is wonderful and overwhelming.
Finally, in all of his tasteless existence, Axel feels something. And what's more is that of everyone around, Roxas chooses him to be pretend friends with. It makes him think he can feel a spark of being worth something, of being special. Yet he is obviously to the fact that it is not just him; Roxas unknowingly affects all of their existences, nudges that wisp of emotion in everyone.
Of course, Roxas leaves as well, ripping a psychological hole in Axel's being. It was worse that when the adrenaline dulled, worse than the fading lust of when he used Demyx. It was like having a drug you can not build immunity to pumped into your veins every day, until suddenly the tube is ripped out with out warning and you are left cold and empty, aching more than you ever were before.
The only thing Axel can feel anymore is that suffocating emptiness; almost agonizing, except not, because he isn't physically able to feel those kinds of foreign things anymore. He never realized how much he could miss this; not until he had gotten a taste of the tangible source, rather than the diluted traces.
It is all he can do not to leave the organization immediately, to go searching for Roxas. To get his drug back, his salvation. He uses his missions to tear the worlds apart looking for the short blonde. He grows reckless in his failure, desperate almost, except not quite.
It is during his hunt that he meets the keyblader. The boy he could honestly care less about, which was saying something considering. But this time, seeing him sends a weak pang through his body. He seems familiar, as if he is something he needs.
Axel talks to the kid, speaks in riddles to hide is own unease, watching him closely. There was just something about him.
It is when he passes too close, nearly brushing against him, that a surge of something he recognizes blazes in his being. And suddenly he understands everything, understands that this is the one. The boy that gave Roxas the transparent memories of emotions; the one who's stolen heart created the nobody that gave him optimism. Seeing him, Axel realizes that Roxas can no longer be found; there is no one to find. Yet what he had found was better than he set out to locate; he had found Roxas' somebody, he had found the source. The product was always more potent at the source then the venue, and this gave new hope (which was something he could actually experience when around Sora, even if it was only a faint glow).
Knowing this, Axel can't stay away from Sora, it's an impulse now. The remnants briefly awakened in him when Roxas was around stirred restlessly anytime he got close to the keyblader. It only took that first time, that first surge of emotion, for Axel to be utterly hooked, far beyond the point of return.
It was for these reasons that he was more than willing to help Sora succeed. It didn't matter the price or the goal, he would help the boy in what ever way he could. It only made sense to Axel that he would guide Sora to the castle to rescue the girl (the one he had stolen to draw Sora to him) and defeat his Superior. What should he care about his comrades? That was exactly the point: he couldn't care about them and they couldn't really care about his constant betrayal.
So it only made sense that he would do everything in his power to help Sora achieve his deepest wishes, even if it meant his own destruction. Anything for Roxas. Anything for Roxas' Sora.
When they are in that strange world between worlds, the place were things are yet aren't, he knows what he must do to let Sora keep going, and he doesn't mind, isn't afraid.
When they are overwhelmed by the creatures that once served him, Axel is perfectly content (a recent emotion he decided he liked very much) with giving everything he had, how ever little he truly possessed, to keep Sora safe. As long as Sora, the boy who houses his Roxas, is okay then so is the remaining fragment of his nobody. So Axel doesn't mind throwing his existence away, it's not like he was truly alive to begin with anyway. There was never any real value attached to his existence.
The kid, Sora, the one that looks so much like Roxas, is looking at him sorrowfully. He's saying something to him, near tears, but he doesn't know what, can't focus, he's too blissfully numb. He smiles, as if he can hear Sora, then mutters something about him looking like Roxas, how he helped him feel. He forces out a sentence about this being his way of giving back to Roxas, by helping his somebody. He hopes (what a strange feeling) that it is enough to rid the keyblader of any guilt.
Axel closes his eyes as his consciousness starts to drift, feeling complete for the first time.
Finally feeling alive.