(In Sister New Devil, Basara didn't acquire Brynhildr until he was 10 years old. He was 15 at the start of the series, meaning that right now, in 1998, when Jack is nearing 11, Basara is barely 5 years old. Jack at the start of DxD, and Shinmai, will be 20 years old.
Basara has another five years before his canonical incident. Also, while Rias, her peerage, is in High School, Jack will have already been graduated.)
While Jack was in the Underworld receiving Procellarum Phantom, back home his Father and Mother sat down at the table. In Esmeralda's arms was a small baby girl with dark black hair and a few strands of blue.
In two years ago, they had conceived their second child. Right now though, they had something very serious to converse about. Esmeralda could just tell from the stern look on her husband's face that it had been eating at his mind.
Hers as well as how she could not know what was going on.
"Esmeralda, we need to talk about Jack."
She sighed as she knew what this was about.
"The accident awoke his latent powers."
Jack nodded.
"Not just that, he most definitely has a Sacred Gear. He has done his best to keep it hidden, but there is no hiding the kind of power he has. I am almost sure he has one of the Longinus if not a new one."
Esmeralda thought back to the past 10 years of peace they had. Yet the near-fatal accident with their son had sent him on the path of the Supernatural. Both of them had been playing dumb about it, but things were changing too fast recently.
Jack was getting too strong and he would soon start to draw the wrong attention to himself. Esmeralda asked her husband a question she was worried about.
"Do you think the Hero Clan will search for him?"
Jack thought about it as he was once the best Hero produced by the American branch of the Hero Clan. He and Jin Tojou were similar in age as they were born just three years apart. Jack in 1970 and Jin in 1973 so he was older than Jin, and they had developed a brotherhood in their youths.
Esmeralda on the other hand was not a hero and was instead a powerful witch from Oz. Ten years ago, at age 18 Jack had relinquished his oaths to the Hero Clan bringing dishonor to himself, and had been excommunicated. All because of who his wife was, a Witch from Oz would never be sanctioned to marry a member of the Hero Clan.
Once they left the clan, he moved to Texas for a few years where he, his wife, and their son lived in peace. Yet, 2 years ago, the members of the hero clan began to pester him to return.
They did however want him to abandon his family, rather than do that he moved to Japan. He has requested permission to live in peace and the Japanese Branch with Jin's persuasion had been forced to leave his family alone.
That was until two years ago when his son suffered a near-fatal accident. Esmeralda had unsealed her magics to heal him to prevent him from dying, but that was when she noticed how his mana had increased substantially.
Over the past two years, that had grown as Jack in secret trained himself which was now causing even the Japanese Hero Clan to start asking questions. Jack sighed as it seemed everything around him was calling him back to that life he had left behind. Esmeralda was at her witts end as for all their son's drive, he was a child in their mind.
Children shouldn't be raised as warriors. Even now, both of them had sealed their magics and strength to live normal lives. They had done the same to Jack as an infant to prevent him from being noticed by Supernatural entities, but all that was for nothing.
Jack looked up before he made up his mind.
"We might as well tell him the truth. He already unsealed his magic, his Sacred Gear, and is training himself. Even now, I have no idea where he went. For all we know, he could be led stray by some Devil if we don't do something."
Esmeralda handed her daughter, Jannet to her husband. She then reached for her necklace and took it off. Her mana which she had not used since she had to heal her son began to rouse itself. She took control of it before breaking the seals she had on her magics.
With that action, the Witch Of Elemental Chaos was unsealed. Her eyes began to glow a mesmerizing glow, like the color of the rainbow with each of the elements. As for Jack, with a flex of his Life Force, his Touki broke all the seals and restraints he had kept for so many years.
A bright blue aura enveloped him as the Hero of The Deep Sea was back. This was something not even Apophis had been able to find out because of the lengths they went to keep this past secret.
Jack stood up with his baby daughter in his arms who was in awe at the lights around her parents.
"When Jack comes back, we will speak to him about his heritage. If he wants to remain in the Supernatural, that will be his choice. In the meantime, I will contact my old friend, Jin."
---
While his parents were having a series of conversations about their future as a family, Jack was sitting down on a chair in Azazel's office. Azazel brought out the Sacred Gear in question. Rather than a physical form, the Sacred Gear was contained in a small purple-glowing magical orb.
"Here. All you need to do is feed it your mana and it will do the rest. We are here to make sure nothing goes wrong."
He handed the orb to Jack who held it in his hands. Just as Azazel instructed, he began to channel his mana into the orb which began to darken as his mana had been thoroughly changed by his contact with Apophis' Soul. This went on for a few moments until it reached the needed amount.
The orb then flew out of his hands and entered his chest. When that happened, he didn't know what to expect, but then he felt it form a connection to his soul just like his Abyssal Eclipse Gear.
When the connection solidified, he felt he could now call on Procellarum Phantom just like his normal Sacred Gear. He stood up from the chair and he focused on the feeling of this second Sacred Gear.
In a surge of darkness, his entire legs up to his hips were covered in heavy plates of thick black metal. He could feel the Sacred Gear enhance the abilities of his legs just like Azazel said.
(Image here.)
Once the Sacred Gear appeared Shamzai who was running diagnostic spells spoke.
"Any discomfort? Do you feel pain or a rejection?"
Jack stretched his legs out before shaking his head.
"No, feels just fine honestly. I rather not test out its powers in this office since I am fast already. I rather not slam into the wall."
Shemhazai smiled at that.
"Seems you're more responsible than Azazel here. Let's take you to the training field. You must want to take them out for a spin."
Azazel snorted.
"Always a stickler Shemhazai."
Shemhazai glanced at his brother with a slight scowl.
"Say that when you do your own paperwork."
Baraqiel cleared his voice.
"Brothers, let us focus."
Azazel nodded with a smile.
"Right, let's go."
Jack sent his new Sacred Gear back to his soul before he followed Baraqiel, Azazel, and Shemhazai to the training field where Baraqiel gave a class to the human recruits of Grigori who had Sacred Gears.
When they reached the training field, it was a large space enchanted to be far larger inside than it was on the outside. The ground was made of soil to cushion the impact of the sparing matches. As such, it was good enough for the test.
Azazel turned to Jack who from the look of it was wanting to go all out.
"Have you pushed yourself in speed recently?"
Jack had not tested his speed since gaining his third pair of wings. He had been focused on recovery, and now that he was back at his new peak he was ready.
"Not since I gained my third pair of wings. Guess I should test it."
Jack walked away from the three Fallen Angels leaving Amara with Azazel. From the look of it, his cat liked the presence of Baraqiel more and she was currently hanging off his shoulder.
Baraqiel while looking rough on the outside was a total softie so he was quite happy to play with Jack's cat. As for Jack himself, he began to jump in place from one leg to the other.
Before becoming a Fallen Angel, he could run at around 200 to 250 miles per hour which was just his human limits. Once he became a Fallen, his speed practically tripled as his physical abilities got enhanced substantially even with one pair of wings.
Now, he had three pairs of wings so his natural physical capabilities had grown to match his new rank. He bent down and got into a runner's position before shooting off into a run. In moments he broke the sound barrier causing a sonic boom as he relied on just his natural speed.
Azazel, Baraqiel, and Shemhazai braced as they got hit with the Sonic Boom, but it didn't seem it affected them all that badly. Azazel put on what Jack could only call a scouter as he measured Jack's speed.
"1,400 MPH and rising."
Baraqiel nodded to himself as he ran a hand through his beard.
"For a former human who became one of us, he is quite fast when not using his magic."
Shemhazai had to agree.
"He is getting faster, as well."
While Azazel kept track of Jack's speed, Jack himself decided to push as hard as he could. He took a deep breath of air before with a growl of extension his speed seemed to almost double reaching up to 2,800 MPH.
Seeing that seemed to make Azazel smirk as most of the high-speed feats in this world were achieved when one enhanced their abillities with mana. That or other magical effects, but that speed was respectable when one just used the strength of their body.
They allowed Jack to continue running for a full minute and for the most part, his speed held steady.
"Jack, your speed stopped increasing. That is your physical limit right now."
When Jack stopped he did so by jumping into the air, spinning around, and digging his hands into the ground. He dug in his legs as well allowing him to crawl to a halt after a few moments.
He exhaled causing hot steam to escape his mouth.
"Phew."
When he picked himself up he dusted himself before walking over to Azazel.
"A scouter? Really?"
Azazel shrugged.
"I take inspiration from any source I can get. This was just something I saw from my kid"
Jack didn't know Azazel had a kid.
"You got a kid?"
Azazel nodded.
"He isn't mine biologically, but he might as well be mine since I have been raising him for the past 7 months. I might introduce him to you at a later time."
Jack was fine with that as he assumed that was Vali. Before they forgot why they were here, Shemezai brought it up.
"Before you forget it is time to test out Procellarum Phantom."
Baraqiel patted his brother on the shoulder.
"Shemhazai, let him relax a bit. Despite his size and bulk, he is ten."
Jack nodded.
"Thank you, Sir, but he is right. Let's get this show on the road."
Jack returned to the training field before he summoned Procellarum Phantom which appeared once more covering his entire lower half in thick plates of armor. He slammed his feet into the ground feeling the strength in his legs had already increased.
"Right then, time for speed."
When he ran forward the sound barrier was shredded as he moved ten times faster. He didn't just break the Sound Barrier as with the new Sacred Gear, he was moving almost 28,000 MHP.
36 times the speed of sound making Procellarum Phantom one of the best upgrades that Jack had received. Thanks to its abilities, Jack's mental faculties were sped up to process these insane speeds.
Jack was moving so fast that he began to cause a dust tornado as he was causing a vortex with his speed. Seeing his creation work, made Azazel start to laugh.
"Look at him go. I think I just made a monster. With his baseline speed and Procellarum Phantom, he will be able to speed blitz even those stronger than him. I can't wait to see him reach his full potential.
Think of it when he becomes a Seraph, unlocks his Balance Breaker, or as he says becomes something above a Seraph. He will be a Speed Demon."
All Azazel liked these days was his Sacred Gears and making them. Seeing one of his creations working was the best reward honestly. Seeing the insane speeds at which Jack was moving, Baraqiel's opinion of Jack was quite high this.
He was already thinking about how he would train Jack. This was also only Jack with three pairs of wings. Just as Azazel said, if he became a Seraph Jack would become something legendary.
"He will go places that is for sure."
Shemhazai felt the same.
"Agreed."
As for Jack after doing a few laps he came to a stop by dragging his speed and using his darkness manipulation to drag him to a halt.
"Damn, I am going to love this Sacred Gear."
[I can see why, an increase of ten times to your speed will always be useful. It could be the difference between life and death. Especially since it will stack with Boosts. You might as well be a Speed Power Type Hybrid now.]
Jack was very much so excited to see what he could achieve at that level. Instead, he walked over to give his report on what it felt to use Procellarum Phantom. Since it felt fine as if it was always with him.