Before learning 'Fairy Law', one has to understand the spell it was based upon i.e, 'Law'. Therefore it was quite dangerous to train it alone. That's why Makarov wanted to supervise it himself. He didn't want to risk anything happening to Natsu. He knew that the current Natsu was even more powerful than himself, and if such a person failed to cast such a powerful spell correctly, the consequences would be disastrous.
But Makarov didn't need to worry about this since Natsu wouldn't fail at all due to his instant mastery cheat that completely no-sells all difficulties in life. No matter how difficult a spell was, he would instantly master it once he learned the proper procedure. As for the lost lifespan, he didn't worry about it at all. He was a demi-god who was basically immortal after all.
Like this, Makarov taught Natsu everything he knew about 'Fairy Law' including the spell it was based upon, 'Law'. Natsu absorbed all the information like a sponge, making Makarov dumbfounded. He was shocked to see Natsu master everything he taught so quickly. In this way, Natsu completely mastered one of the three great fairy magic in a single day, making Makarov shocked beyond belief. He could only shake his head while thinking about the unfairness of the world. It took him more than a decade to master the spell, but Natsu mastered it within a single day.
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When Natsu returned to the guild, it was already dark. All the guild members had already left the guildhall for the night, with only a lone Mira cleaning up the place. He stealthily crept up behind her and pulled her into his embrace, making her squeal in surprise. She wanted to fight back but Natsu stopped her.
"Relax, it's me," Natsu said before blowing into her ear, making her shudder in pleasure. She relaxed a lot when she heard her lover's voice.
"Geez, Natsu… You almost gave me a heart attack. I thought some pervert wanted to attack me." Mira said while pouting, visibly dissatisfied with his earlier actions.
"I'm sorry, I couldn't resist hugging you when I saw you all alone in the guild. Where are the others?" Natsu asked while resting his chin on her shoulders.
"Everyone's back home. You should see the time, it's already time for dinner." Mira replied before continuing her work, wiping the dust from the table with a wet cloth. It didn't stop Natsu from hugging her though.
"Hmm… What about Erza and Kagura?" Natsu asked curiously while playing with hair, twirling it around his finger.
"Well… Both of them left a few moments after you left with master Makarov. They were clinging to each other as if they were childhood buddies, but it kind of looked like Erza was the big sister of Kagura. Do you know anything about it?" Mira asked curiously. Natsu nuzzled against her smooth neck, causing her body to heat up.
"Yea Kagura told me about it," Natsu said before telling Mira about Erza and Kagura's past, which surprised her quite a bit. She didn't think that her rival had such a tragic past. Erza hadn't told anyone about her past in the guild except maybe Makarov, but even Makarov didn't have the full details.
"Sigh… And here I thought I had the most tragic past. I guess my past suffering couldn't even compare to Erza's. You better take good care of her. She's suffered enough and clearly needs some happiness in her life." Mira sighed when she thought how much her rival suffered in her childhood. She was a kind girl and didn't want to see her family getting hurt.
"Of course I will. I won't let her be hurt anymore. I'm going to end her suffering once and for all soon." Natsu replied with a determined voice. He was going to end her suffering once and for all by destroying Jellal and his Tower of Heaven. He wouldn't kill him, but that didn't mean he couldn't make him suffer for his crimes.
Mira smiled when she heard his voice. She knew Natsu wouldn't allow anyone to hurt his family. That was one of the reasons she fell in love with him.
"I'm glad to hear that. Now can you get off me, please? I need to tidy this place up and head home." Mira said, urging him to get off her.
Natsu smirked and started grinding his hardened member against her rear, making Mira moan cutely.
"Before going back, why don't we have some fun?" Natsu whispered seductively into her ears, making her whole body shudder in pleasure. She felt her whole body heating up after hearing his voice.
"N-Natsu we shouldn't… This is the guildhall… W-What if someone comes by?" Mira asked while stuttering. She felt aroused by just thinking about having a hot make-out session in the guild, but her rational mind prevented her from acting on it.
"Don't worry about it. There's nobody in the guild right now. I've always wanted to pound you in the guild while you're wearing your barmaid outfit." Natsu replied while bending her over a table. Then, he pulled her skirt up and slowly removed her panties. She was dripping wet down below, with her juices leaking down her thighs.
"I guess I'm not the only one who wanted this," Natsu smirked and pulled his pants down, revealing his hardened dragon. Mira was embarrassed, but she couldn't deny his words. She was indeed aroused thinking about Natsu hammering her inside the guild.
Then, Natsu inserted his rod inside her fold and started rutting inside her, making her moan loudly. The guildhall was filled with a pink atmosphere, erotic moans, and flesh slapping sounds. Thankfully, no one was nearby to hear the erotic sounds of their favorite idol getting brought to heaven by Natsu.
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~Edited by Nyanodesu
Read up to chapter in advance at my p@treon:
p@treon. com /xumit
(A/N: Well I got my channel back finally. It took fricking 20 days for YT to respond. Anyway, enjoy this chapter ^^)