Found it

Lisa came in to check up on Mark, who hadn't left the confines of that room for the remainder of the day. It was like the good old days when he'd simply sit inside his room, alone, working on whatever it was that piqued his interest. Gone were those days of familiarity, days when he could go meet those he held dear to him like it was nothing. Perhaps they'd come back, but only God could tell.

"Mark, are you alright? I'm a little worried since you didn't come out all day long."

Mark turned towards her; a few books opened before him, laid bare on the table. His notebook was already filled halfway, his right arm shaking from all that writing.

"I'm fine; thanks for checking in on me. I still have some work to do here since I've learned some interesting things."

She regarded him with a worried look, yet the passion he exuded was enough to ward her off, since any attempt to stop him would only end up futile.

"Fine, but promise me you'll come out and at least eat something."

Mark looked at her with a bit more care, this time focusing solely on her. She did seem to be worried for him. Somehow, that made him feel a certain emptiness.

With a weak smile, he spoke.

"Sure, I'll come out later and eat. I still have some work here, so let me finish this, then I'm out."

She nodded, walking out, leaving Mark to his own study. His gaze swooshed back to the pages filled with text about all sorts of magic. At first, he learned as much as he could about what things could be done with elemental powers, and to his surprise, the list seemed to stretch on and on.

It had it all, from mundane things like doing work faster to complex things like reading one's future. Of course, Mark was against that, and he believed it to be just a silly way to see a possibility within one's actions. Despite all that, he did remember Mona and her prescriptions being accurate, at least to a certain degree.

"Well, that's the basis of elemental powers. I don't need that; I have what I need. Now, moving on to the interesting part."

He read along, following what the book referred to as myths—stories of old about a different type of magic that is said to have been part of the world at some point. That was something he had a little idea about.

"The abyss... perhaps these things are related; who knows?"

He kept reading, finding something rather interesting that he had never heard about: dragon tongue. It was but a brief mention, referring to a language that is said to have been spoken only by dragons.

"I'll be damned. Perhaps we screwed up the plot a little too much. Well, it's worth looking into, yet I highly doubt there's any way to learn that."

A sudden flash struck him, the scene of him speaking those words flashing before his eyes. He pulled out the piece of paper he had with those words written on it.

His eyes hungered for it, drawing them in like Venti drinking wine.

"Eziot calam naum."

Nothing happened. 

"Quite the anticlimatic moment. Well, I'm sure there's something to it that I'm missing. A catalyst of sorts, like a dragon's powers..." 

He thought for a moment, recalling his first adventure after arriving in Mondstadt. A fragment of the power Dvalin was using still burned somewhere within him.

"Perhaps it could work, but I'm not sure. Hopefully, I won't blow up."

He stared at the neatly arranged books, shivering at the thought of his punishment if any damage had been done to the books.

"Perhaps I'll try outside."

He wrote a few more things in his notebook, taking great care to make it as readable as he could, since his usual handwriting was a mess. With a few careful strokes and pained groans, he finished, finally relaxing his wrist for good.

"Alright, this should be it. I'll tidy up a bit, then head out."

A few more minutes passed, and he could see the light go out as less and less sunrays got in through the little window the room had. He walked out, noticing that the library was desolate, filled with an eerie silence that reminded him of hallway scenes in horror movies.

"I'm out." 

He ran for the door, feeling his back run cold as he grabbed the door handle. Sure, nothing came for him, yet the feeling was too vivid. This was one of those times he'd curse his realistic imagination, blaming it for the moments of awkward fear he felt.

"Finally done?" 

Lisa's words caught him off guard, his legs tripping against one another as he backed away, almost falling. Lisa grabbed him by the collar, something she did out of reflex, managing to hold him up as he rebounded himself. She stared at him as her hand held on, pulling him closer.

"Oh my, are you planning to break my heart as well?"

Mark's face flared up as she joked about the subject, yet he felt it sting a little more than it should have.

"Struck me where it hurts most. Truly, I'm afraid to think about the harm you could inflict on someone if you really tried. Thankfully, I got zero fucks to give most of the time."

She let go of him, smiling at him as if nothing had happened.

"I'll just warn you against getting on my bad side."

She giggled softly as she winked, giving Mark the message loud and clear.

"Got it. Well, I'll go grab something to eat. My mind is burnt out right now, and I think I'll go to sleep after eating, be it whatever hour it may be."

"Mind if I join you? I'd like to talk about your little 'study session'."

He sighed, nodding for her to follow as he walked out.

"You know, sometimes I wonder, why am I acting like a nice guy? Heck, I hate being alone, but at the same time, I miss my solitude."

Lisa giggled, walking beside him.

"You can't have both, Mark. Become greedy, and you lose both."

He said nothing, taking a deep breath as he contemplated something. Most of the time, he found himself thinking about things, some of them holding a certain value, while others were merely triffling matters.

They reached Good Hunter, the place where Mark had been with Aether and Paimon just a little while before.

"So, what do you plan on having?" asked Mark, taking a seat at an open table.

"I think I'll go for something simple, like a soup."

Mark chuckled, recalling something.

"Hm, perhaps I'll have something with pumpinks."

Lisa shivered, and despite her best efforts to mask it, Mark had seen enough. He chuckled, standing as he went to order.

"Don't worry, I'm playing with you, Lisa. I'll have my usual drumsticks with salad."

Said and done, Mark went ahead and ordered, returning with an amused look on his face. Lisa seemed to be slightly embarrassed as she avoided looking at Mark.

"Cheer up, Lisa. I'll help you smack them to pieces if we happen to come across them."

She looked at him despite seeming even more ashamed.

"You should see what people do where I'm from. During a certain period of the year, they basically carve them to be as creepy as possible, and they place candles inside. It's funny to do it."

"Can you please stop talking about pumpkins?" asked Lisa, slightly annoyed at that point.

"I had to get back at you for that little comment of yours back when I left the library. Now we're even."

Sara, the waitress, came with a bottle of wine and two glasses, which Mark took with thanks.

"My, you sure are a romantic at heart. Wine, the comfortable atmosphere of an early night."

Mark chuckled, pouring some for the two of them.

"I simply felt like having a glass. The one I had earlier today left a bit of a bitter taste, so I thought I'd try to change things up a little."

Without hesitation, he downed the glass, putting it down with a light smack.

"I needed this. I'll sleep soundly, and heck, even the biterness is gone now."

Lisa kept glancing at him as she sipped from her glass, tipping it slightly before slightly parting her lips.

"Bitter taste, huh? Well, let's leave that aside, since I'm a bit curious about your research. What exactly were you looking for?" 

Mark stared blankly for a few seconds before asking.

"You won't let me get away with a lie, right?"

She nodded, showing him a few purple sparks as she rubbed her thumb and index together.

"Lying to a lady will only make things worse."

Mark sighed, speaking openly as he poured one more glass.

"Well, I had no idea what I was looking for, but I did figure out that something like a dragon's language exists in one form or another. Be it truth or simply myth, I hope to test it out at one point." 

He avoided talking about the words he himself had spoken while in a frenzy, instead focusing on the language itself. 

"Dragon tongue? I see, so you were looking for magic other than elemental one. You're not the first to do that, but perhaps you'll be the first to succeed with something grand." 

He chuckled, thinking about what sort of insanity he could come up with if he messed around with his powers, thinking about his unusual red aura. 

"Perhaps I'll do something funny, but until then, I'll stick to what I know." 

Their food came as well, which Mark began eating eagerly. His stomach was in dire need of nourishment. 

"Maybe I should have had at least a snack while I holed myself up in that room." 

"Maybe you should have. You sure looked like you were hungry." 

He laughed, remembering how much of an appetite he actually had. 

"Well, it's not my fault that I could eat a horse like every day." 

They shared a laugh, and their little outing soon stretched into the night, the sweet taste of wine tingling Mark's tongue as they spent their time together.