A Grigori Agent.

Jack waved his hand and he released a hypnotic spell that caused everyone around them to stop paying attention to them. Azazel nodded as that was a basic spell all Devils and Fallen Angels knew so he wasn't surprised. 

However, when Jack extended his right arm and called on his Sacred Gear he was stunned as a black and crimson gauntlet appeared in front of him. 

"I can see you have never seen this one before. I present to you the Abyssal Eclipse Gear, a former Twice Critical that now contains the soul of Apophis." 

[That would be me.]

Azazel knew Apophis had been killed, but God had never made a Sacred Gear from that Dragon. Since Jack did say it used to be a Twice Critical that meant this happened after his Death. 

"Apophis how did you end up in a Twice Critical?"

[How did you get made? I have no clue, I just wound up in this Twice Critical and then I got sent into the Heaven System before ending up with Jack here. I am almost sure, the one who killed me sealed me in a Twice Critical to prevent me from reincarnating. He did make a new Longinus-level Sacred Gear though.]

Azazel was teaming with curiosity as he looked at the large Black Gauntlet. 

"Kid, you are going to go places. A Fallen Angel hybrid with a never-before-seen Sacred Gear. How many pairs of wings have you got right now?" 

"Two, if I am honest I think I might grow my third soon." 

Azazel was alerady feeling quite proud. 

"Good to know. I will say this now, welcome to Grigori." 

Jack smiled as he knew that he would gain more out of joining Grigori than the Devils. 

"Glad to join, sir." 

Azazel scoffed. 

"Call me Azazel, when you call me Sir, I feel like a fossil." 

[You are a fossil.] 

Azazel ignored Apophis as Jack dismissed his Sacred Gear. School could go to hell when his future was in his palm right now. Azazel now went on to explain a few things. 

"Since you are so young, you won't be taking any missions unless you want. The most that is going on now is just Sacred Gear observation. Sure, some Devils are causing trouble, but Heaven, Grigori, and The Hero Clans are keeping them in check. 

The monster clans as always keep to themselves and the Shinto Gods follow a similar stance. This time is peaceful, so I can take you to the Underworld to show you how to teleport to our base." 

[I am sure the peace won't last.]

Azazel shrugged. 

"I rather it did."

Jack nodded as he did want to see the Underworld. However, he used his contract with Amara to recall her to his side. In a flash of light, his sweet giant cat appeared on his shoulder.

"We are ready to go." 

Azazel smiled. 

"Nice cat." 

"Thanks." 

Under them, a large custom teleport circle appeared and took Jack, Amara, and Azazel to the Underworld. Specifically in the territory of Grigori in Azazel's office. When Jack appeared in the Underworld he instantly felt that the Mana in the air was far more concentrated than on Earth. 

"Are we in the Underworld?" 

Azazel grinned. 

"Yes, we are. Welcome to the secret fortress of Grigori. Been standing since times immemorial. Since this is just your first time here, the most important thing is confidentially. You can't tell anyone about this place." 

"I understand. You want me to sign a magic contract or something. Give you a sliver of my soul like a cultivator." 

"Hell no. Just don't tell others and you are fine."

Azazel placed a hand on Jack's head which in a year or two would be funny. Azazel was 6'3, but Jack was set to surpass him in height soon enough. Azazel then transmitted the coordinates and the method to teleport into the Underworld. 

Jack focused on the information which he quickly assimilated. 

"I understand." 

Azazel was happy he got it that fast. 

"Great, the fortress is quite huge so I won't give you a full tour. I am too busy for that and I will just assign someone to the job. I will introduce you to my friends at a later time, but I will tell them about you. 

You will be fine with Baraqiel, Amaros, Penemune, Sahariel, and Tamiel, but be careful with Kokabiel and Satanael. The former will either try to kill you, and the latter will try to experiment with you." 

Jack decided to give him a friendly warning. 

"Azazel, if Kokabiel tries to kill me and I kill him, will I be punished for that?" 

Azazel shook his head. 

"If he tries, snow no mercy. He has been getting more and more uppity these days, but he is still my brother. I rather it not come to that so avoid him." 

"I will try." 

After that talk, Azazel walked Jack around the main important areas. He took him to the forges where all the gear and weapons of the Fallen Angels were made. The training rooms which used gravity magic to make training more effective. 

Azazel also showed him a gym with weights made of extremely dense materials that could be made heavier through magic. That was going to be Jack's favorite place, and after the training rooms, Azazel simply took him back to his office. 

However, Jack felt so much was left out of the tour. 

"That can't be the whole tour." 

Azazel nodded. 

"It's not, but I have seen everything for centuries, it is boring. Explore on your own." 

Jack sighed. 

"You old beings are lazy." 

Azazel nodded without any shame. 

"Yes, we are, when you live as long as me, putting effort into anything, not your hobby is hard. I rather be researching Sacred Gears or inventing something awesome. Like yours for example." 

Jack smiled as it was time to get what he wanted. 

"Who says I will let you research it? Laziness does not reward effort." 

Azazel's smile faded. 

"Man, you kids are getting smarter. What do you want?" 

Jack thought about it before pointing at Azazel. 

"How about some of your blood? I should be able to use it to enhance the latent talent of my own Fallen Angel bloodline. I wasn't born a Fallen Angel as one of them tried to kill me so I fed his body to my Sacred Gear and Apophis made a Blood Essence for me. 

He was weak with only two pairs so I am worried that his blood's talent will dry out." 

Azazel for a few moments went quiet as he looked at Jack who might as well have said he wanted to harvest him for ingredients. 

"Wow, kid, first meeting and you're already asking for my blood." 

Jack just pointed at Azazel. 

"Hey, you're the one who wants to study my one-of-a-kind, Sacred Gear. I think that is fair, what is few blood bags." 

Azazel wanted to laugh at the absurdity. 

"You don't just want a vial, you want blood bags, plural. What is next, you will want one of my kidneys." 

Jack nodded. 

"Good idea, you can grow one back can't you? I will graciously accept a kidney, some liver, and a few of your feathers. Maybe an eye to sweeten the deal. In exchange, I will so graciously let you study my Sacred Gear. That sounds fair."

 "FAIR MY ASS! Do I look like I can magically regrow organs?" 

Jack shrugged. 

"A few potions and healing spells and you would be good as new. But I understand, that trading your organs must be too far, I will return to my initial request for some blood. Perfectly fair trade-off." 

Azazel sighed as he had a better idea. 

"How about a Sacred Gear instead? I got several, Twice Criticals, a few Vritra Gears, or some of my own creation. Doesn't that sound better in exchange?"

[How about you give us a Sacred Gear and some blood. You can make sure Jack doesn't use it for nefarious things. It will make him stronger in the long run and you will gain a powerful agent for Grigori. Fair?]

Azazel grimious as these two were like sharks out for his blood, literally. He thought about it as the idea was not lost on him as he was the only Seraph Fallen Angel in existence. He was at the top of his race and having even some of his blood would allow Jack to have an easier time reaching that rank. 

After carefully thinking about it, it wouldn't inconvenience him that much. He even had lots of his blood collected incase he ever needed a blood transfusion or for potion work. 

"If and I mean if I do do this for you, let's set some ground rules. You will have to use all of it in front of me since I don't need Apophis teaching you some curses. If it works, I will assign one of my friends to mentor you in supernatural combat. 

I will train you myself in your Sacred Gear, and I will be allowed to study it. Plus, you can pick out a second Sacred Gear from my stockpile. Does that seem like a fair trade?" 

Jack nodded. 

"Yeah, that sounds fair to me. I don't intend to cause you harm since I rather learn from you as my senior in the supernatural world. Plus, consider this just me trying to make the best of my situation. The way I became a Fallen Angel was by refining a weak Fallen and even with my Sacred Gear, the potency of his blood might dry up.

So I want to go to the strongest Fallen Angel, you." 

Azazel sighed as he stood up from his desk. 

"You really are something, fine." 

Azazel waved his hand and the wall behind his office opened up into a gigantic laboratory. All over the walls, behind glass cases were Sacred Gears that he had collected over the centuries. 

Some were gauntlets, boots, or other parts of armor. Others were weapons, like shields, swords, and spears, and others were immaterial. As such they were contained in magical lanterns to prevent them from returning to the Heaven System. 

"Welcome to my laboratory where the magic happens. Here, I study the Sacred Gears I have collected. I also invent my own Gears that have all kinds of effects. Sadly, they are still a work in progress and are not as straight out as powerful as the more refined Sacred Gears that Pop's made." 

Jack nodded to himself before looking at Amara. 

"Hey Azazel, you think my cat could get a Sacred Gear?" 

Azazel thought about it. 

"I do sometimes give out Sacred Gears to my best people, never gave it to an animal before. Do you want to use up your Sacred Gear on your cat?"

Jack shook his head. 

"No, I was just wondering. Regardless, I don't need a weapon-based Sacred Gear as I can make those by making Dark Light Constructs, Shadow Constructs, or solid Primordial Water." 

Azazel thought about it. 

"What is your fighting style?" 

"Up close, fast, unrelenting, and explosive." 

Azazel began walking around his collecting as he had ideas. 

"How about a defense-related Sacred Gear?" 

"No, I am pretty tanky especially since my Sacred Gear can still use the Boost from the Twice Critical. Not as high as the Boosted Gear, but still good enough." 

When Azazel heard that he now really wanted to study it. 

"Got it, you don't need a healing Sacred Gear, or a weapon Sacred Gear. No defensive ones either, and you are a Fallen Angel so you're more survivable than a human. I think I got an interesting one a movement speed-based one. I also based it on the Twice Critical which your Sacred Gear used to be."

Now Jack was curious. 

"Which one?" 

"I call it Procellarum Phantom, it forms a set of armor focused on your legs up to your hips. Rather than strengthen your entire body, it enhances everything about your legs by a factor of ten. The strength of your legs, ten times as fast, ten times as impactful when you kick. 

If you can use the Boost still from the Twice Critical base, you will be moving faster than fast. I only have one though and it is untested. You could test it out for me." 

Jack pondered on this as it could synchronize quite well with his gauntlet-based Sacred Gear. When he went to Balance Breaker, he could merge both Sacred Gears making him many times faster, and stronger simultaneously. 

"I like it, I will take that one." 

Azazel smiled. 

"Glad you appreciate my work. I can implant it soon, but you also want this right?"

Azazel touched a touchpad on the wall before something came out of the wall. From what he could see, it was a safe that Azazel opened. He reached inside before pulling out a blood bag. 

"My stash. This safe stops time inside so these are straight from the source despite the fact they are labeled 1967. Very few can make me bleed so I barely use this. How many do you want?" 

[Let's go with two. Two pints of blood should be plenty.]

Azazel pulled out another bag before closing his safe. 

"Alright, how are you going to do this?" 

[I would recommend removing the same amount of blood from Jack and then replacing that blood with yours. Through Magic, he will be able to use the much stronger Fallen Angel genetics to enhance his own.] 

"Makes sense. You can just sit in that chair, I will draw your blood. You can have it back if you want since that can be used to curse you and I don't need you thinking I tried to curse you." 

"You can keep it if you want to study how my genetics work. I will trust you just like you are trusting me with this." 

Azazel nodded as Jack sat down. He removed his school uniform shirt leaving him just in a black tank top. Azazel began to gather some equipment to draw blood from Jack. It was rare to find someone so agreeable to Azazel didn't mind this. 

Azazel's hobby was the most important thing to him and he had to know more of Jack's Sacred Gear. If he had to give him a Sacred Gear and some blood in exchange for him joining Grigori, that was a fair trade in his mind.