Natsu hadn't been a demon for very long, at the most it had been an entire two months, although that would only be by estimation seeing that the eldest of the Dragneel's had not been keeping track of something so petty and not of any real importance. Zeref had been working furiously in his room nearly the entire time to try and figure out a way to lock away his younger brother's side effects that came with reviving him from his previous 'slumber' -which is what Zeref had told the little four-year-old when he'd woken up. Natsu had been holed up in that room with the dark haired male for the entire time due to his obvious demonic traits. The youngest had two small horns curling up from his skull, barely peeking out of his now pink tuffs of spiky hair.
The boy not only sported horns, but a set of small fangs; two of which were so long they poked over his lower lip. His ears were no longer round-shelled like that of a human's, either, but now came to small elvish points and were able to move similarly to that of a dog's. The most obvious of all the side effects were the black marks that start and sprout from his spine in thick, vicious lines of which resemble jagged tentacles of tougher skin. In fact, if not for his age Natsu would resemble the stereotypical image of a incubus with the small useless wings that sprout from between his shoulder blades and the thin arrow-tipped tail that dragons on the ground behind himself when standing and walking around. Of course Zeref had to examine the human turned demon to get an idea on what he'd done to him.
At the moment Zeref rubbed at his brow giving an irritated sigh as he worked himself to near exhaustion. Natsu was in the background babbling the poor raven haired boy's head off, half his words just pure jibberish. Although four years old, the child hadn't had much one on one learning time with his parents. He had the patience of an untrained filly, being in that it was hard to get the energized Dragneel to stay still for more than five minutes and focus. Natsu wobbled around in his long shirt that hung past his hips, making obnoxious noises as he bounces his stuffed toy around on shelves to interact with other handmade toys. Eventually, Zeref gave in and closed his book to turn and watch as Natsu made his way around the room in small steps.
"Natsu…" he started, leaning back in his wooden chair to prop his head up with one hand, elbow resting on the arm. "What in Earthland are you doing?"
The pink haired boy pauses in his steps and swivels around to face Zeref, pointed ears twitching up to show his focus is on his older brother. "Hum…'m playin, Zeze!" He informs, thrusting a short arm forward to shake his stuffed toy at the other.
A brow raises, "I can see that, but do you have to be so loud?"
Oblivious to the question, Natsu's head bob's in a quick assuring nod directly before he turns back to playing. It took about five more minutes of this repetitive actions for the eldest brother to have enough and stand to leave the room, patting the small boy on the top of his head with a demand of "stay" before slipping from the crowded space, barely catching to confused tilt of head and glance Natsu gave him at that.
Thanking the gods who didn't curse him, Zeref left to go make them both a quick meal, even though Natsu didn't technically have to eat. He lived off the book of E.N.D. something as silly as starvation wouldn't kill him. Perhaps make him a little grumpy, however, with how much he loved stuffing his face to make the biggest food mess possible.
The peanut butter and jelly sandwich making was a short lived moment of silence when a terrified shriek made its way through the home the Dragneel's lived at alone ever since their original home burnt to the ground at the hands of a rogue dragon. Zeref dropped the butter knife instantly, startled, before bolting back to the bedroom with a hand of black energy raised defensively in his palm. However, the scene he'd flung the door open to was not one he'd expected to see.
Natsu sat in front of a large mirror leaning against the closet on the ground. He'd clearly fallen back with the way his legs were curled out in front of himself and one arm was behind, supporting his weight. He stared down his own reflection, eyes wide and lip trembling as alligator tears rolled down round cheeks. Confused, Zeref lowered his hand and walked closer to Natsu, not yet touching the boy, simply deciding observation would be best for the time being. Natsu hiccupped softly and struggled back to his feet, taking extra small and wobbly steps forward with a hand outstretched to press to the glass, against his reflections own hand.
The pinkette flinched back the moment he made contact, and stumbled away, wings flaring out from apparent instinct to make himself appear larger to what he considered to be dangerous. This action from himself only made him scream once more and turn to dart directly into Zeref's legs, clinging and burying his face in his thigh as he sobbed. That's when it clicked for Zeref, who scooped down to pick his brother up and cradle him in his arms as best as he could.
"Oh Natsu, are you terrified of your own reflection...?" He questioned while heading over to the mirror, turning carefully so the other could cautiously peek over his shoulder at himself.
"M-monsturh." He squeaks back in his horrified tone, dipping his head back down to hide his face into Zeref's shoulder.
That stung the black wizard more than it should, causing him to even flinch and tighten his hold on Natsu while watching his tail swish beneath him. He shushes him softly, walking over to the bed to sit down on the edge, pulling a notepad over. Afterwards he situated the crying demon to settle comfortably into his lap, although still clinging.
"Here, Natsu, pay attention to me." He said calmly, tapping a pen to the paper. "Would you like to help me create a friend like you, so you're not alone?" Zeref offers a small smile.
"A frund?" Said demon questioned, turning his face from Zeref's chest to look down at the paper. With a shy nod he reached forward to grab the pad and pull it into his lap.
Satisfied, Zeref brought the pen forward to start writing ideas down, simple one's such as gender and magic. Natsu piped up with his own ideas, helping his older sibling to create what are now known as the Nine Demon Gates. First came the idea-only creation of Mard Geer, who with time developed into one of Natsu's imaginary friends who led to his comfort with his demonic self. He didn't feel so alone when he believed Mard Geer to follow him around on house-only adventures. Natsu's imagination would produce wild ideas such as how the other would cheer him up by blossoming flowers from just the palm of his hand to let Natsu sniff at.
Mard Geer had been the first demon the black wizard had officially created outside of bringing his brother back to life as one. Once clothed and having developed an understanding of why he was a creation whose life laid on the pages of a book. Natsu had cheered up the moment he'd seen Mard Geer in person. The tall male cracked an awkward smile and kneeled down to be a little more eye level with the child who bounded forward to tackle him in a hug, short arms wrapping tight around the official demon's neck in a warm hug while his pointed tail flicked back and forth excitedly and he giggled in Mard's ear.
When Natsu's demon traits had finally been sealed away completely in the book of E.N.D. it was discussed privately between Zeref himself and Mard Geer as to what would happen with Natsu. His brother was to be…well, abandoned. Igneel would pick him up as his savior, and would raise the other as an all-powerful dragon slayer. It had hurt when Natsu had been left, not only did Zeref hide himself away for his awful deeds, but as did Mard Geer.