A/N this is an alternate ending to the original story. I hope you enjoy it.
Gray's POV
His time was running short. He had used too much of his life force in that fight. Then continued to fight with Natsu on almost empty. Guilt knawed at him for not telling his friends that they would never see each other again. At one point he opened his mouth to say goodbye but nothing came out. Only able to watch in sadness as they one by one entered the portal. Loke was the last to go with a knowing look in his eyes. One that begged him to find someone to forgive him for what he had done. Instead he smiled sadly and lifted a hand in goodbye. Loke's eyes watered but he too lifted his hand. Fairy Tail members only said goodbye when they were going to die after all.
Turning to the onlookers he knew there was one more thing he had to do. One more thing before he disappeared. He took the life of a Celestrial wizard. With the last bit of his life force he would give another the ability of a Celestrial wizard.
Unsteadily he made his way to the others. Benjamin stood with a gentle smile. One he didn't deserve even after he helped save their world. That man had taken him in. Given him a friend and confidant.
Once he was close enough to touch the man he asked," Ben do you trust me?"
For a moment the man stood there with a dumbfounded look. In that moment he thought the trust was only one way. It almost made him rethink his plan.
Then the man said with confidence that made Gray want to smile," I do, Gray. You have never given me a reason not to. On top of that you saved us all."
That was all he needed to know. With a determined look he remembered how to make a necromancer into a Celestrial wizard. While it was taught to every spirit it was rarely used. Only a handful of spirits willingly spent time in the human worlds.
Closing his eyes he focused one last time on his magic. As he grapsed it his resolve strengthened. While this wouldn't earn him forgiveness it would set things to rights.
Placing his hand on the man's chest he focused. Searching till he found the man's core. It was dark as was expected for one who was a necromancer. At the same time it was powerful. He had chosen well it seemed.
Taking a deep breath to settle his anxiety he began," I am Lupus of the Wolf Celestrial gate," There was a sharp intake of breath that he ignored," I bind thee to the Celestrial world. By doing so I give thee the powerful over Celestrial spirits to call upon as allies. I gift this upon thee."
Their magics intertwined fulfilling his command. Opening new pathways for the man and his line. The Nott family would have the potential to be Celestrial wizards from now on. There was one more gift that he needed to give though. One that would not end with his passing.
Pulling the key hanging from a silver chain over his head he held it up. The Wolf Gate key. An extremely rare sight for Celestrial wizard and spirit alike. Few had ever seen it. In the world of Earthland it had passed into nothing but legend. A forgotten tome to a brutal past.
The next in line could prove what he was unable to. That darkness didn't mean evil. With the help of Ben they would live a better life. Hopefully they would also meet Fairy Tail. That was an experience he would never regret.
He dropped the necklace over the top of Ben's head. The key now lay heavily over Ben's heart.
Steeling himself for one last bit of magic he proclaimed for magic and those watching," As my final act as Lupus Gate of the Wolf I freely give my key to Benjamin Nott. Head of the Nott family. From this point on he is a friend to the Gate of the Wolf."
A golden light entwined around them. Magically binding the Gate to the man and his line. When the light faded he collapsed. Last of his strength was draining from him. This was it. This was where he would disappear forever.
Ben asked bending down next to him panic evident in his eyes," Gray what's happening?"
It was Marvolo who answered," He's dying. Isn't that right, Mr. Fullbuster?"
A choked out a laugh. Of course Marvolo had figured it out. That man was smart. Much smarter than he gave him credit for. He felt his magic tearing at his core and insides. Not only had he overdone it in the battle, but now his magic was trying to tear him apart. It wasn't unheard amongst other Celestial Spirits. If one continued to use their magic once their life force was gone. The magic would tear apart the wielder's body and core.
He smiled sadly as he said," In fact I am. How long have you known?"
"Some thing was suspicious about your arrival the entire time. Dying explained a lot. Though it doesn't explain how you are dying."
Gray sighed as he looked up at the stars. So the man's suspicions never faded. At least he wasn't a fool.
So he answered honestly wincing as his body began to fade more heavily this time," I committed at terrible sin. One that broke Celestrial law. This is the price I pay. My life force draining out of me. If I had avoided using magic I could have lived for a year or so. My high use of magic and this battle drained what I had."
He stopped before he went even further. He didn't want Benjamin to feel any guilt. The man had done so much for him. It had been his choice to use the very last of it to give the man his gift.
Benjamin said angrily," Damn it Gray. You can't die. Not for a mistake!"
Gray couldn't reply as a sharp pain went through him. His body almost completely faded that time. His beastial magic was tearing at him. Internally he felt his core shatter. Even if he was allowed to return to the Celestial World he would not survive. This was where he would die.
Pushing through the pain he said," I'm sorry, Ben. This is goodbye. Thank you for your friendship. I'm so glad I got to meet you."
Ben's warm brown eyes widened. Realizing that Gray was giving up the man wrapped his arms around the black haired young man. Hugs were not a regular thing even in Fairy Tail. It took him a long moment to realize it was a hug. Ben was pushing his magic into him. Instinctively trying to force a contract.
The man growled," Open Gate of the Wolf! I send thee back to the spirit world."
He almost wanted to smile at the man's actions. He was beyond saving now. If it had been before the battle he could have been saved. Now not even the strength of the Celestial King could save him.
Gently trying to disentangle himself from the man he said," Stop. Ben there is nothing you can do. Nothing can save me from my fate."
No one could fix a shattered core. As it stood in that moment he was a living breathing deadman.
Marvolo asked bending down next to them," You won't be able to force his gate open like that, Ben. What did you do that was so forbidden, boy?"
Gray's eyes widened then went sad at the question. Whispering softly he replied," I killed a Celestrial wizard. He had been abusing another Celestrial Spirit. I couldn't stand by and watch her get hurt. She was Loke's friend. We fought and I ended up kicking him over the side of a cliff. It was an accident but one that had dire consqueneces. Since then I have been banned from the Celestrial world. Unable to replenish my life force. Here I will die because of that mistake."
A strange look crossed both men's face. Ben asked," Do you think we have enough combined power?"
Combined? They were going to continue? Why?
Instead of answering Marvolo placed his hand on his abdomen. Right on his almost drained and destroyed core. The power that coursed through both men was incredible. Instead of helping him the euphoria only lasted a moment. Then the pain returned in excess. It tore at him like a starving monster.
Once more his body tried to disappear. If someone was looking at them they would be able to see Ben's leg on the other side of him. This time his body only partially returned. He was still mostly see through on his left side.
He tried to push them away but Ben stopped him growling," Stop it. You can't die! Whoever decided that you were guilty is wrong!"
The rising magical power exploded. Knocking the three of them apart. Off to the side he saw a few of Marvolo's men try to move toward them. Only to stop. It was as if they were frozen in time.
Gray's eyes widened in realization. He swung around to see magic swirling. A familiar form began to appear.
He said surprised," That's the Celestrial Spirit King!"
The elder spirit glared at him for a moment. Then turned his gaze assessingly on the two men. Marvolo and Ben both stood proud. Their gazes never wavering.
Spirit King said in his low baritone voice," As you well know, Lupus Celestrial wizards and spirits must obey Celestrial law. Taking the life of a key holder is forbidden under any circumstance. It seems you have overdone it, Lupus."
Gray smiled faintly as he said sadly, "That I did. I do not regret my actions in this case. Protecting this world isn't wrong."
The king nodded his eyes softening, "Yet you regret killing your key holder. You maybe darkness but your heart is pure."
"What happened was an accident. You can't fault him for protecting both himself and a fellow spirit."
Marvolo... the man's red eyes glared fiercely at the spirit. It surprised Gray how much the man cared. Outside of Fairy Tail no one cared that much before. It felt nice that someone would play advocate for him. Even if it was all for naught.
King said," No matter his circumstances he broke the law. As such he is being punished. If one broke the law in your world. Would they be punished?"
Ben growled," Not by death. He is just a child! Some of us apparently know what forgiveness is more than others!"
The King said magic swirling around them, " Then as promised when I exonerated Leo the Lion with these men's forgiveness. You, Lupus the Wolf, are hereby granted return passage to the Celestrial World. Though I fear it has come too late to save this incarnation of you."
Ben asked his voice shaking, "What do you mean? He's been granted passage back to the Celestial World! He can regain his life force."
Life force would only drain out of him again. Without a core there was nothing to keep his life in him. His body faded again and it took all of his self control not to cry out. He must have made a sound because Ben propped him up against the man. When he looked down he had faded from the waist down to almost nothing. It was his time.
To Ben he said his voice barely above a whisper, "Ben... listen to me... I won't survive this. There is nothing that any of you can do for me. My core shattered in the fight and my magic is tear... ugh... apart my body. When I die a new Celestial Spirit will be born here. Please... look after whoever it is. I trust you and Marvolo to look after him."
Ben went to interrupt him but Gray stopped him saying, "Don't! Just promise me... please..."
His breaths were coming in short pants now. It wouldn't be too long before his magic finished the job that his life force started.
Ben promised, "We will look after him. I swear upon my magic that we will look after to the best of our abilities. So mote it be. "
There was a flash of the man's magic. Then there was a burst of pain and a sharp cry from both Ben and Marvolo. Then he knew no more.