His meeting with Zeref gave Ben a better understanding of his current power level. In terms of raw power, he was definitely stronger than Zeref. He knew that Zeref's magic was troublesome and the difference in raw power can be ignored.
Still, at least he knew he had a chance to defeat Zeref. The only problem now was determining how to sever Natsu's connection to Zeref. After that's taken care of, there will be nothing stopping from killing that guy.
Ben worked on determined how to solve that problem as soon as possible, so he started his research 2 days after he encountered Zeref. He was working in his hidden lab that Future Lucy mentioned before returning to her timeline.
The hidden lab was very big and it's location was deep under the village Cait Shelter operated in. It's location was also the reason one of it's entrances was inside the cave he and his sisters used to train in the past. Ben only used that entrance when he isn't home.
Jarvis is also connected to this lab because this lab is connected to his house. Jarvis's presence was the reason why Ben didn't explain much to Future Lucy. She will find out anything she needed to know from Jarvis who will recognize her and the magic mark on the back of her hand.
Currently, Ben was opening some black books in an isolated room. He's trying to come up with a way to sever Natsu's connection to Zeref, so he is looking through the Books of Zeref that he collected. Ben had read through all of them, but he tried to find something different, so he checked them again.
"Damn, it seems the only way to do this is finding the Book of E.N.D. If I just remove the Demon Seed from Natsu's body, he'll die. It's his core of life, so I can't simply remove it. However, if I leave it be, then it might turn him into an evil Etherious and erase his personality." Ben said to himself.
Ben thoroughly inspected Natsu's body a few times while the idiot was asleep. He could clearly feel the Demon Seed due to his Devil Slayer Magic. But Natsu's Demon Seed is dormant and didn't show any signs of activity.
Even so, Ben was worried that the Demon Seed might suddenly activate and grow. Natsu's Demon Seed is different from the one in a Devil Slayer's body. He was a demon from the beginning, while Devil Slayers are human.
Ben knew that right now, there's a dragon's energy inside Natsu's body. He knew that energy was Igneel's energy and soul. He found a similar case in Wendy's body, so Ben knew it quite well.
Igneel's energy is suppressing the growth of Natsu's Demon and Dragon Seed. However, a dragon's energy will only stop dragonization courtesy of the Dragon Seed. The Demon Seed will not disappear and it will be activated once again after the dragon's energy is depleted.
Ben knew this because it was also happening to him. He also had a Demon Seed in his body as a side effect of his Devil Slayer Magic. And of course, his God Slayer Magic also created a God Seed in his body.
But his seeds were unique because rather than being 3 different seed, there was only one seed. So that one seed contained the power of a Sun Demon, Sun Dragon and Sun God in it. Ben still can't understand why the 3 powers merged into one seed which was just a Dragon Seed in the past.
The unique seed has 3 colors on it's skin and was surrounded by colors of flame-like energy. There is a blood red color that represents his Sun Devil Slayer Magic, a gold color that represents his Sun Dragon Slayer Magic and a black and gold color that represented his Sun God Slayer Magic.
It is really strange, but it also relieved Ben instead of worrying him because those 3 powers are cancelling each other's effect out like demonization and dragonization. Natsu's case is different because his Dragon Seed is getting weaker. Unless Igneel's energy destroys the Demon Seed too, Natsu might turn into a demon.
"Problems keep popping up one after another these days. Let's not think about it too much for now. I can always subdue Natsu if his Demon Seed suddenly grows. Besides, I don't need to worry about that as long as Igneel's energy is still there. So at least I still have time to figure this out." Ben said. He had decided to stop thinking about this matter for the moment.
There was something more important for him to do right now. He went to a massive room which was also part of his lab. This room's original size isn't that big actually, but he used Space Magic and increased it's space and size, so the sizes inside and outside of this room are different.
Well, it's confusing, and the easiest way to understand it is that this room had a lot of space. It was big enough to fit three dead dragons inside it and there is still a lot of empty scale. The 3 dragons were the ones that Ben killed during the Eclipse incident.
Ben stored them in another dimension with his Space Magic. That's why they didn't return to the past like Atlas Flame and Zirconis. The other dimension's time isn't affected by this time, that's why these dead dragons are still fresh.
Currently, Ben is extracting all their blood and stored their blood in 3 different containers. All parts of a dragon are valuable, especially for a Dragon Slayer like him. He can use them to increase his power and help him defeat Acnologia.
Many cables and pipes are also connected to the dragon's bodies. They were used to extract all remaining magic power inside the dragon's bodies. Ben didn't want to waste anything, even the remaining magic power that he can use to enhance his power.
Maybe it's because his seed was unique, Ben's overall power actually grew when he defeated demons or dragons. So killing demons or dragons will also affect his Sun God Slayer Magic. The effects are higher on the magic that matched the slain enemies, but the other magic was still affected.
"Jarvis, how's the blood extraction?" Ben asked.
{It's proceeding well, sir. It will be complete in 4 minutes and 46 seconds.}
"Good. In the meantime, let's start the next procedure." Ben said as he went to the center of the room.
In the center of the room, there was a big, round hole that was 1 meter deep. Many small glowing blue magic circles were placed all over the hole. Even more magic circles are placed on the ceiling above the hole. These are all Anima magic circles that Ben used to gather magic power from another universe.
4 minutes later, the blood extraction was finally completed. Ben then poured all the extracted blood into the hole and made it a pool of blood. Then he strips and floats on the center of the pool of blood naked.
"Jarvis, start the procedure." Ben said as he dipped into the pool of blood.
{Understood. Please get ready, Sir.}
{Initiating Project Ultimate procedure.}
Suddenly, all the Anima magic circles glow brighter and more magic power poured in. A magic barrier made of complicated magic letters also appeared around the pool and isolated it. Many small black magic letters also appear on Ben's entire body.
Ben suddenly flinched before he screamed. "AARGH!"
Suddenly, Ben felt a lot of pain all over his body as the dragon's blood started to evaporate. Blood red mist filled the inside of the barrier room and and Ben vanished from sight. Only a scream of pain can be heard from him. What transpired for someone like him to scream painfully like that?