Because in my headcanon they all love him in some way. This somehow turned into a little character study on why they all follow him, but I'm not quite sure if I like the result or not. Maybe some of you can give me opinions. Enjoy! :)

Love In The Equation

All of them knew about it.

It couldn't have stayed a secret for long with everyone living on the same ship, especially not when they were so close. Each of them saw it in the others' subtle glances and lingering touches, in the rare acts of affection and even rarer kind words. No one ever tried to gain the upper hand because no matter what they felt it would never be returned in that way and they knew that. But since the one person in the center of it all was too oblivious to notice the truth anyway they didn't really have a reason to hide it either.

To everyone's surprise it had been Zoro who had first voiced his thoughts out loud, right after their battle in Alabasta when Luffy had still been unconscious, lying surrounded by his nakama who had one by one gathered around his bed with no intention of leaving.

"He's amazing, isn't he?"

The admission hadn't been quite as much of a shock as the softness in Zoro's voice or the tender edge around his eyes that spoke volumes no amount of words could ever measure up to.

For a second everyone had simply stared at the swordsman in wonder before synchronously turning towards their captain and smiling that same soft smile.

"Yes. Yes, he is."

They didn't speak of it again after that, simply acknowledging the fact that all of them shared the same feelings towards Luffy and silently accepting it.

When they reunited after two long years of separation and saw Luffy smile just as widely as he had before the crew had been torn apart – before his brother had died in his arms –, they all felt as though they could finally breathe again. It should have been strange just how much a group of random people depended on the happiness of one boy, given how stubbornly independent they had all been not too long ago.

But it wasn't. Not to any of them.

Least of all to Nami. She had been his the moment he had told her to be, standing among the rubble of her own personal hell as she'd held onto the treasure he had entrusted to her. Without blinking an eye he had saved her old home and given her a new one, full of dreams and promise and carefree laughter. It might be harsh on her to deal with some of the idiocy on board every day, but one look at that brilliant smile and she knew that there was nowhere else she ever wanted to be. So she adjusted the sails, following down the path he had chosen, determined to take him to the ends of the earth if he asked.

Nami's devotion to him was similar to that of Robin. Her past was a dark one, bloody and destructive, leaving a trail of pain and loneliness in her own personal history. She too had been lost with no place to return to until Luffy had shown her the way, without giving advice or the words of wisdom she was used to taking from books. Just his presence, his powerful aura and the meaningful D in his name had lured her in, unknowingly tangling her fate with his. And when she had seen Enies Lobbie's flag fall to ashes and screamed for help for the first time ever since her people died, he had heard her. And that had been enough.

Over the course of their adventures Usopp had found a true friend in Luffy, the man who had forgiven him when he'd thrown it all away and who'd protected him always, against all odds. It had taken some time for him to realize that it wasn't the ship they sailed on that made him feel home, it was Luffy himself, and the realization hit him hard. Luffy gave him strength simply by believing in him and his laughter was the only thing Usopp felt he could never live without. While he knew that he would never be strong enough to stand by Luffy's side as Zoro or Sanji could, he would always give everything he had to support his captain. And if that meant simply telling him stories on the uneventful days to make Luffy laugh and keep a smile on his face at all times, then he would gladly do it for the rest of his life.

Chopper loved Luffy like a brother would. He felt connected to him on a level that went far beyond any he had ever known, beyond that of human or beast, only comparable to the bonds he'd experienced in his time spent with doctor or doctorine. This was a bond that would never shatter, one that had made him feel confident in himself and in his place in the crew, one that had linked his dream to another and given him strength. Luffy didn't fear him. Luffy understood him and that was more than Chopper could have ever hoped for. In this man who'd seen him not as a monster, but as a friend, he had finally found the place he belonged.

Luffy and Franky had not started off on the best terms. It had taken a declaration of war and a few near death experiences for the cyborg to see Luffy for who he really was, a man among men. Franky didn't give his respect to just anyone, and never without a good reason, but this man who had surpassed all of his expectation, this man he knew deserved every bit of respect he had to offer. Having the future Pirate King – which he would be, Franky was sure of it – sail on his dream ship towards the ultimate romantic goal a man could have had filled him with a sense of peace and excitement at the same time. Luffy had given him so much more than just a place to stay. He had offered him a chance to follow in the footsteps of his adoptive father and finally make amends with his past. And for that Franky would be eternally grateful.

It didn't happen often, but now and again Sanji caught himself thinking about where he'd be without Luffy. On the Baratie still? Hunting for the All Blue by himself? There was no way to tell, but in Sanji's mind one thing was for sure. Without Luffy he would still be lost. Trapped in the guilt of owing the shitty geezer more than he would ever be able to repay, confined in the East Blue without a chance of following his dream like he wanted to. 'It's easy to throw away your ambitions', he'd used to think. What a joke. If he'd thrown away his dream Sanji would be nothing. And it was thanks to Luffy that he was now with them, on the Grand Line, looking for a sea that might or might not be out there. But no matter what, Sanji knew that he would forever be the straw hat ship's cook. And as long as he could hear Luffy's obnoxious whining for meat – always more meat – he didn't need anything else to be happy.

Brook had lost everything. His captain, his crew, his life, his shadow and his way back to the one friend he had left behind. He had been in a dark place, waiting, always waiting, even as the days blended into each other and hours became years with no end in sight. His mind had drifted further and further towards insanity and it had scared him like nothing else ever had, that he might lose this last part of himself that he hadn't yet. Luffy had found him like this. And Luffy had healed him without even trying. Brook knew that nothing could ever bring his old crew back to life and he still grieved for them every day, but he truly believed that his gruesome fate had a purpose now. Because getting the chance to meet these people was something that Brook would never want to miss, no matter what it had cost him. Luffy was the man that Brook had sworn his life to – even though he was already dead – and he would stay by his side for the rest of his days to lighten his heart with music and laughter. If he could just do that and be of help to this man, then his life would be a life well spent.

Where Luffy went Zoro followed. Where Luffy faltered Zoro backed him up. What Luffy asked Zoro would see done. They were like the moon and the tides, like magnets drawn to each other, two beasts on the same wavelength. Zoro knew that this would never change, no matter what might still happen on their journey. He was a prideful man, he knew that, and he could say without gloating that he had quite a few achievements made that he could be proud of. But nothing – nothing – filled him with the same sense of pride that he felt when he looked out to the horizon and saw that boy with the straw hat sitting there on their figurehead, knowing that he could say 'This is the man I follow.' Zoro's ambition had always been what he lived for, what he would one day die for and what he treasured most. But now he knew that if it was for the sake of this man, whatever it might be, he would gladly give everything he had. He needed Luffy. And he found peace in the knowledge that, no matter how strong his captain might become, Luffy needed him, too.

In the end none of them could have named the exact moment they had fallen for him. If asked they would say that it was inevitable, that it happened over time or that it had been a first sight kind of thing, even though for many of them this wouldn't be the truth. One thing was certain though.

What Luffy gave you, you always gave back. And this was never more true than when it came to warmth and laughter and happiness and friendship.

And love. Especially love.