Fantasy Assassin in a modern world

The moment Loki heard Michael's question he immediately understood what had happened. The Spirit of the Akashic Records must have tricked this poor naive little student and told him about Loki's skill. All these thoughts came to Loki in an instant and he was able to respond without missing a beat. 

"Huh, what are you talking about, a mage? Are you asking me if I'm like a street magician or something?" 

When Michael heard Loki's question he sighed. He had already expected this outcome but hearing it was still disappointing. As he was about to apologize for the weird question the Spirit of the Akashic Records spoke to him. 

'Don't believe what this jerk has to say, he's lying to you. Not only is he a mage that knows about mana, but he's also of a rather high caliber.'

'Are you sure? The look on his face doesn't seem like he's lying.' 

'Who are you going to believe me the omniscient Spirit of the Akashic Records, or that lying b*stard?'

'... Well, even I'm not really sure if you're real or not.' 

'What?! Fine, I'll prove it to you, just say what I'm going to say verbatim and I'll show you the true colors of this guy.' 

Loki stared at Michael who stopped talking, as he was about to say something, Michael suddenly spoke. 

"I'm sorry Sir Loki, what I meant to ask is if you have any more books regarding Mages."

"Oh if that's all you wanted to ask, you should've spoken to me sooner I am after all the librarian, and helping you find the books you need is part of my job." 

"Sorry about that, I'm not really good at striking up a conversation." 

"That's alright, I just hope that next time you just be upfront about it. So then what kind of books about Mages are you looking for?" 

"Anything really, since I already read most of the occult books in the library, I'm not sure what else you have." 

"Is that so, tell me what books you have already read, and I'll see if we have more." 

Michael nodded his head and proceeded to list all the books he remembered reading. As Michael was talking Loki felt that something was off, but he wasn't sure what was wrong. The two of them were having a simple conversation, nothing more. Once Michael was done listing the books he waited for Loki's response. When Loki looked at Michael he couldn't find anything strange, as a precaution he used his mana sensing but that too revealed nothing. After a short pause, Loki finally answered Michael. 

"I see, so the books you have read are those." 

When Loki answered he noticed Michael was giving him a strange look. 

"Is there something wrong?" 

"Sir Loki, did you understand what I just said a while ago?" 

"Huh, of course, I understood it, is there a problem?" 

"Sir Loki what I spoke wasn't any known language in this world. It's only something a person that can use spell words could understand." 

When Loki heard what Michael said he finally realized why he was feeling so apprehensive before. He was tricked, the moment he thought of that Loki started thinking of a way out. It should be that irritating Spirit that was guiding Michael's words. 

"Sir Loki no matter what you say now, I won't believe that you don't know anything about mages and mana." 

"..."

"Sir Loki please teach me how to gather mana." Michael looked at Loki with a firm gaze. Seeing the resolve and determination in Michael's eyes Loki hesitated. After a long pause, Loki sighed as his entire demeanor changed. 

...

Michael who was waiting for Loki's answer suddenly felt a tinge of fear as the surrounding atmosphere became heavy. Michael then noticed Loki emitting an oppressive force that made him instinctively want to flee. Even the Spirit of the Akashic Records was telling him to run away. Yet despite all these warnings, Michael stood his ground. 

"So that's how it is..."

Loki mumbled to himself. He had tested Michael's will by emitting his killing intent, the same killing intent that could even make an experienced warrior kneel in fear. Yet this boy that hasn't been in a true life and death battle has stood his ground. This meant that except for death nothing will stop the boy before him. 

"Before I answer your question, I just need to know a few things. Did you activate the system the Spirit offered?" 

"Yes," Michael nodded his head. 

"I see... I'm guessing with the incomplete knowledge of that Spirit he's unable to teach you how to increase your mana supply and since all the spells it knows require more mana than what you can produce you went to me for help, isn't that right?" 

Michael looked at Loki in awe, it was like the librarian was able to see through his thoughts. It would seem that the librarian was more mysterious than he thought.

"... That's right." 

Loki sighed before responding. 

"Fine, I will teach you how to gather mana and increase your mana supply, but I have one rule you need to follow. It's a simple rule, do not tell a single soul about my capabilities. If you fail to follow this one rule, then I will make sure you'll be unable to talk to anyone else for eternity." When Loki said his last sentence he emitted killing intent that was three times stronger than the last. "Do you understand?"

Michael gulped as he nodded his head. Loki then approached Michael and tapped on his forehead, he felt something suddenly enter his body. 

"Just to make sure that you keep your word I placed a spell on you. If you even think about telling my secret the spell will activate and you will go into your final sleep." 

'Is there really such a spell.' Michael asked the Spirit. 

'I don't know, my knowledge is incomplete, but it is possible that there really is such a thing.' 

"Of course, you can still change your mind now, If you tell that Spirit to never suggest something like this ever again, I'll wipe away the memory of this conversation and remove the spell I placed on you. So do you agree under all these conditions?" 

"I agree to everything, please teach me," Michael answered without any hesitation.