Natsu had just attacked Zeref with all his might. When the smoke dissipated, it was clear that Zeref had survived the attack. Natsu was on his knees on the ground out of breath.
"Are you okay?" Happy and Luna asked Natsu.
"I'm good. Don't worry, I'm good enough for one more attack... Igneel I need your strength. One more shot is all it's gonna take." Natsu said as his dragon tattoo started to disappear from the bottom.
"Let me have a shot at him, Natsu." Luna said as she had Elise start flying her down toward Natsu, but he put his hand up, signaling for her to stop in her tracks.
"No, please stay back. Keep yourself and our child safe." Natsu said as Zeref straightened himself.
"I'm impressed. You've grown so strong, it's true. If there's anyone alive who can stop me it's you. At least, that's what I've wanted to believe. But so much time has passed. I shifted my focus away from destroying myself some years ago and directed those wishes toward the world at large. This moment has, once again, changed things. Although I am immortal, your next strike could very well end my life. Yet another contradiction. It all depends on your strength. With that said, I have something to share with you. This may be the last chance I ever get." Zeref said as Natsu panted, bringing himself to his feet.
"Huh?" Natsu said in a confused manner.
"My true name is Zeref Dragneel. I'm your older brother." Zeref revealed as Natsu, Happy, Luna, and Elise looked at him in shock.
"About 400 years ago, both of our parents were killed by dragons. They were burned alive. I lost my entire family that day... including my little brother Natsu." Zeref continued as Natsu eyed him suspiciously.
"No way, I don't believe it." Natsu said as he eyed Zeref.
"For years, I tirelessly researched ways to bring you back from the dead. Instead, I created new life. Etherios otherwise known as demons from the Books of Zeref. You are one of those. Originally named Etherios Natsu Dragneel or E.N.D." Zeref explained as Natsu just stared at him in shock.
"He's lying! Why would you believe a word he says?!" Happy suddenly shouted at Natsu who snapped out of his shocked state.
"Yeah! So I'm supposedly your dead brother and some kind of demon you made? I've never heard such a load of crap! Anyway I thought Igneel wasn't able to beat E.N.D. We all know he could've totally crushed me whenever he felt like it. So there's no way that's me." Natsu yelled at Zeref. Luna on the other hand had a feeling Zeref was telling the truth but she kept that to herself.
"It's not that he couldn't physically defeat you, brother. He simply refused to out of fatherly love." Zeref explained to Natsu.
"Huh?! What about E.N.D. being the demon that made Tartaros?! That ain't me! Besides, I'm human!" Natsu yelled, clearly in denial and disbelief.
"Mard Geer was responsible for bringing Tartaros into being. He happened upon this book by sheer luck. Then used it to gather other demons claiming it was the will of E.N.D." Zeref said as a reddish-brown book with the letters END on the cover appeared and fell into his hand.
"So one could still make the argument that you created Tartaros." Zeref said as he tossed the book aside.
"That's enough! There's no way in hell I'm a demon!" Natsu shouted in anger. Suddenly Zeref shot a small beam of magic from his finger through the book and Natsu reacted like he had been shot in the chest and fell to his knees. Then Zeref went on to say that he still couldn't reason with Natsu even after all these years like back then which is why he consulted Igneel because he didn't know what to do with him. The fact that Zeref and Igneel were friends shocked him. Zeref explained that Igneel was one of the few dragons that harbored no hostility toward humans at the time. They met by chance while he was out collecting herbs for his research. He then started to explain that Igneel offered to share his knowledge with Natsu and teach him dragon slayer magic because of a plan he, Metalicana and the other dragons had made. They would raise dragon slayers and use the Dragon Soul Technique to seal themselves inside them to travel to the future to slay Achnologia. They needed to go the the future because there needed to be more ethernano in the environment. He explained the children chosen for this were Natsu, Gajeel, Wendy, Sting, and Rogue all ones without families. Well Natsu had Zeref as family but he gave permission for Igneel to take Natsu in because he wanted Achnologia dead but he also hoped Natsu would grow strong enough to kill him and end his suffering. Then he went on to explain how they ended up in the future.
"They used the Eclipse Gate to create a portal into the future. A celestial wizard named Anna was in charge of the entrance. The exit was left to an undetermined point in time. Anna's family passed this responsibility down for generations. The gate was finally unlocked in this current era when ethernano was abundant. A celestial spirit wizard named Layla opened the Eclipse. That event happened on the seventh day of the seventh month of the year X777, the day you felt the dragons disappear. In fact, it was the day you dragon slayers awoke in this era. You were children, ones born 400 years in the past." Zeref said as Natsu just stared at him in shock.
"I waited for you. Centuries spent in on anticipation. However 400 years is a long time. Much has happened since then. I've seen ages come and go, countless people being born only to die. For a while the importance of any one life lost meaning. Then I met Mavis and inevitably lost her." Zeref continued. Natsu lost his patience at that point.
"Shut up! I don't believe any of this crap you're spewing!" Natsu said as he lunged at Zeref with his flaming fist drawn back, preparing to deliver a powerful fiery punch.
"Since you're a demon of the Book of Zeref, if you kill me, you will die too." Zeref said but Natsu didn't seem to care about that.
"If that's what it takes then so be it!" Natsu yelled as he continued making his way towards Zeref.
"Natsu!" Happy shouted as he raced towards Natsu.
"I've already made up my mind! I came here for one reason only! To take you down for good!" Natsu shouted as he got closer and closer to Zeref
"This is your last chance brother. Please don't fail me." Zeref said with tears falling from his eyes. But right as Natsu threw his fiery punch, Happy had grabbed him and pulled him back so that the fire didn't reach Zeref. Both he and Natsu were surprised.
"What the hell's gotten into you Happy?! Take me down!" Natsu yelled at Happy whose paws were burned.
"I can't let you do it! You'll die!" Happy said while tearing up.
"If I let that happen, I couldn't live with myself, Natsu." Happy said, through his tears.
"I'm losing Igneel's power so you gotta put me down. This is our last chance. If he gets away, he's gonna destroy the whole world!" Natsu said, trying to convince Happy to let go of him.
"But you're my best friend, Natsu! You'd stop me from dying, would you?!" Happy cried out, trying to make Natsu understand as he carried Natsu away with Luna and Elise following close behind.
"I'm taking you home no matter what. Right now." Happy said with tears dripping from his eyes. Natsu just hung there in Happy's grasp.
"Natsu... how could you?! Being willing to just sacrifice yourself like that! Not only leaving Happy behind, but me and our little one as well..." Luna started out shouting, punching Natsu on the shoulder but then her voice got quieter as she placed her hands on her belly as tears started to leave her eyes as well.
"Luna... I ... I'm sorry. I was reckless and wasn't thinking clearly. I was so fixated on killing Zeref that I didn't consider how the consequences would affect all of you." Natsu apologized.
"It's okay, Natsu. All that matters is you're alive now. Don't worry, we'll find another way to defeat Zeref without you dying." Luna said as she gently grabbed Natsu's hand and squeezed it lovingly. A small smile appeared on Natsu's face as they flew back towards the Fairy Tail guild hall.