Silmeria - Thanks for being patient everyone. Enjoy the chapter.

Disclaimer - I claim no rights to One Piece or Sentinel.

Chapter Three - A Promise

"You're leaving?" Luffy flinched when the waves rushed over his naked feet, but despite the cold, didn't remove his eyes from Ace's apologetic gray ones. He lowered his own back to the white sand and refused to look back up when Ace reached for his hand to intertwine their fingers together. It was unfair for Ace to come here and-Luffy shook his head and took his hand back and twisted the end of his frayed blue shirt. His grandfather told him that Ace would be leaving eventually, but Luffy didn't want to believe him. After all, it had been an entire year since Ace arrived to Dawn Island and the Sentinel seemed pretty comfortable, so much that Luffy had no doubt that the older boy would be leaving, but he was proven wrong when he saw Ace's packed bag by the door. Seeing such a thing caused his heart to skip a beat and it lead to an entire day of avoiding Ace and his grandfather, to the point where Garp gave him nothing but a sympathetic look once he found at the base of Mt. Colubo surrounded by the bandits who gave Garp stanch looks but handed the boy over nonetheless-one didn't interfere with Sentinel-Guides family affairs.

"I'm sorry." Ace murmured, reaching for Luffy's hand again, smiling sadly when the attempted touch was rejected. He was anticipating it, but it still hurt. He was so used to the little Guide's touch and it felt cold not to receive it now. "I'll come back-"

"You-" Luffy swallowed, turning to face the seemingly endless sea. "You shouldn't make promises that you can keep, Sentinel Portgas."

Ace looked as if had been struck at the formal tone Luffy adopted. There was only one time that Luffy called him that and it was when Ace nearly left the island because of their epic argument over Ace's over-protectiveness. It ended with apologies and a first kiss on the cheek, but Ace never got how cold Luffy sounded towards him. It wasn't something that he wanted to hear again.

"It's a promise that I intend to keep." Ace protested gently. "What in the world makes you think that I won't come back for you, huh?" Ace reached for Luffy's hand once more, ignoring the rejection and took it in his own, holding it tightly and with as much love as he could convey. "Don't you know how much I want you? Want you to be my Guide?"

Luffy swallowed, lowering his head and feeling the heat come to the surface of his cheeks. He hated it when Ace made him feel embarrassed. Of course, he had an idea that Ace wanted him to be his Guide, but to outright say it? It wasn't something that Luffy was prepared to hear. How did Ace expect him to let him go after saying such a thing?

"I..." Luffy raised his eyes and met Ace's expecting gray eyes. "I almost wish you hadn't said that, Ace." he felt his cheeks heat again at Ace's raised eyebrow. "How do you expect me to wait now? How do you expect me to wait when you told me that you want me to be your Guide?"

"You're not the only one waiting, Luffy." Ace stated softly. "I'm going to be waiting, thinking, and wanting you too." Ace's own cheeks flushed at the confession. "Everyday I'm gone I'm going to be thinking about you."

"Why are you leaving?" Luffy asked, swallowing the lump that formed in his throat. "Why are you leaving when you feel this way towards me?"

"I told you about the dream of crossing the Grand Line, going beyond it?" Ace waited for Luffy's nod before continuing. "If I stay, I can't accomplish my dream and if I can't do that then I won't be capable of taking care of my Guide." Ace looked contrite, as if the words coming from his mouth were weak and ineffectual. As if he didn't believe it himself. "I'll be back-"

"I can't come with you?" Luffy asked quietly, staring out into the open sea, the same sea that would take Ace away. "Why can't I come with you?"

"Even if that's what I want, Garp would never let you go, Luffy. Not yet." Ace sounded disgruntled and wounded, but Luffy made no move to comfort him. Why should he, when he was being so hurt?

"You'll come back?" Luffy asked once more. "You promise that you'll come back?"

"I promise." Ace grinned and turned to face Luffy whilst tilting his chin up. "Can I have a kiss before I leave? For good luck?"

Luffy's cheeks heated at the request, staring at Ace's strong cheeks before his eyes drifting down to his lips. Those lips that grinned and frowned and expressed his entire face and Luffy couldn't help but lean closer and press his lips against Ace's, elicting a startled gasp before it turned into a soft moan that caused Luffy to pull away, his cheeks still burning and his lips tingling at the previous contact. He couldn't believe he did such a bold thing, but he didn't regret it.

He would never regret it.

"Whoa." Ace sounded amused and in awe of the kiss, his tongue swiping over his lips as if to memorizing the taste and how well it would serve him on his journey. "Luffy."

"Something to remember me by?" Luffy tried softly. "A kiss on the lips to help you on your way?"

"Right," Ace leaned in and pressed his lips against Luffy's lightly, smiling at the blush he earned. "Right, one more kiss for the road?"

"I suppose one more wouldn't hurt."

Ace left the shores of Dawn Island bright and early the next day with only Garp and Luffy as his farewell party, which he didn't mind at all. The villagers weren't particularly fond of him, only tolerating him because he was a guest of Garp's, which, again, Ace didn't mind at all. He arrived with meeting Luffy and Garp and he would leave by them seeing them off. To him, that seemed like the perfect ending.

His Striker was well oiled and stocked and waiting by the dock located by the small cave that he and Luffy explored more than once during the previous year. It felt strange seeing it again one last time. The urge to explore its depths was heavy in his heart, but he brushed it away. He would be coming back and he could see it once more, this time with Luffy.

"Getting nostalgic, boy?" Garp asked with a grin, his eyes fond. Over the past year, Garp had come to accept Ace as someone who would be good to Luffy, and also who would keep the boy out of trouble. Too many times did Luffy wander off and run into Pirate Sentinels who caught wind of Luffy's sweet Omega scent. Internally, he was amazed that Ace managed to fight off groups of Sentinels despite being a young Alpha, but what caused him to become secretly wary of the boy was his easy manipulation of Haoshoku Haki which granted one the ability to dominate the wills of others. It was a rare and extremely powerful ability and it was one and a million chance that Sentinels, let along Humans were able to obtain it.

Either Ace was born with it, or he had obtained during his time at sea or during his year on the Island. It wasn't uncommon for Sentinels to unlock new senses being around their destined Guide and it might be just the case with Luffy and Ace. However, Garp had become wary enough at that point to research who had bore Ace and unfortunately, was unable to find the boy's file due the high birth rates around that time and the fact that it was most likely that Ace wasn't born in a hospital. It was becoming more and more common these days that Sentinels and Guide parents forego hospitals for a natural, at home birth, in order to avoid the military and potential recruitment. Sure, they were offered money in return for the agreement, but there were some who often disagreed with the military's methods and avoided the hospitals until it became vital that they received care, which was why village doctors became widely popular-less paperwork and prying eyes.

"A little," Ace responded, his fingers caressing the knife gave to him as a parting gift. "It's...rather difficult to leave him. More difficult than I imagined."

"You don't have to leave." Garp offered, feeling sympathetic for the boy's internal plight. He, too, knew what it felt like to leave his Guide behind for a period of time and it was an uneasy and sick feeling. "You can wait until Luffy grows up a little."

Ace looked thoughtful at the proposition. It would be easier, wouldn't it? To allow Luffy to grow up a little, bond, and take off towards the seas? To have his Guide beside him as they sailed all of Blue and into the New World? It sounded wonderful, but something at the back of his mind was telling him to keep Luffy here, a little while longer. He had a feeling that Luffy had great potential and not all of his paths lay with Ace. Not yet.

"It would be best if Luffy remained here until he grows up." the words sounded like ash in his mouth, but Garp gave an approving nod and allowed Ace to continue. "I have all the faith in the world that Luffy and I will meet again and that I will return here to this very spot." Ace lowered his head, spotting Luffy near his Striker as he inspected it, a worried frown on his brow. The sight of it made him smile. Luffy didn't show it, but he was somewhat of a worry-wart when it came to the people he loved.

The people he loved.

Ace loved Luffy with all that he had and he wanted nothing but the best for him. He wanted to be able to take care of every whim Luffy had that it wouldn't be a second thought to him in terms of money or food. And for that to happen, Ace had to obtain his own territories. He wanted to become an Alpha Sentinel in all manner of the words. And if that meant leaving Luffy-his Guide-on Dawn Island while obtaining such a thing, then so be it.

"He loves you without material possession." Garp stated quietly, understanding Ace's true reason for leaving. "He doesn't need all of it, but the Sentinel inside you, that protective side, cannot help it and I understand. Woodslap and I were considering-"

"No, Foosha Village belongs to you and Woodslap." Ace protested. "I don't want your land, I want my own." Ace clenched his jaw. "I want my own lands, to take care of those who wander and my Guide."

"Good. You make sure to do that while away then and come back to get what you desire." Garp ruffled his hair, a toothy grin plastered on his face. "Luffy! Come say good-bye to Ace!" Garp nodded one last time, before turning on his heel and returning to the house that waited just beyond the village.

"Your ropes weren't tight enough." Luffy scolded once he was within hearing range. "Are you trying to get lost at sea?"

"I'm sorry." Ace murmured, leaning down and pressing a kiss on Luffy's cheeks and smiling against the skin as it heated. "You're always looking after me."

"I'm , you know?" Luffy muttered sourly before a chuckle escaped his lips. "You'll be careful, won't you? Send me letters when you can?"

"Yes, and yes," Ace pressed another kiss to Luffy's cheeks, trying to memorize the feel and taste of Luffy's skin pressed against his own. "I'll send you letters whenever I stop in a city. I promise." Ace pressed one last kiss against Luffy's cheeks before stepping away and heading towards Striker with Luffy on his heel, his lips tingling and his inner wolf purring at the sense and smell of his Guide. He would make good on his promises.

"Be good," Luffy called out over the engine of the Striker as the wind increase, as if blessing Ace on his journey. "Come home soon!"

Home

Ace lowered his head to avoid Luffy seeing his wet eyes. Yes. He would come home and soon so that he would see Luffy again. So that he would claim his Guide. He supposed that he would look back and slap himself. He knew better than to think that Luffy would wait too long. He didn't imagine meeting Luffy on these vast seas with a crew of his own and powers that rival even the best of Sentinels. He never imagined that his and Luffy's path would cross in the most unexpected ways.

Then again, Luffy always did manage to surprise him.