Magical Girls are the Best Toys

 Yui, Vili and Miyu together with the demonic wolf, which has again turned into its plush form, came to the Magic Garden where Yui intended to strengthen her demons by saturating them with mana from the Magic Tree. When they saw how the garden had changed they couldn't hide their surprise, the demons have worked continuously since their creation and the results were indeed remarkable.

Starting from the beginning, when they entered the magic zone, they noticed a pebble path that quickly turned into a path lined with even, diced large stones of various colours. What's more, the colours of the stones were arranged in a pleasant pattern. This path, three hundred metres from the border, was divided into three parts: One went further and the others evenly to the sides. They did not know that this path is around the whole garden symmetrically leading from each barrier artefact.

When they approached the centre, they noticed that many trees were cut down in the centre of the garden and their wood was put aside. The ground was roughly leveled with all the unnecessary stones and roots removed, leaving an even, green lawn with shades of purple, giving nice scenery. The path makes a big circle around the Magic Tree which is now on an island which is surrounded by a stream of water on both sides, where it passes through the path there is a small stone bridge.

The very fact that the stream changed its position by a dozen or so metres surprised them, but it created a nice aesthetics so they allowed it to be, without unnecessary questions. On an island near the tree there was a wooden table with two chairs, they were made such that it looked as if the tree had grown in this specific way and the carpenter was just removing the bark. 

"What is that?" Asked Miyu, pointing to something behind the trees on the border where the trees were no longer being cut down. When Yui looked there, she noticed that her demons were building something. Though for the time being it only had a stone foundation, but the scale was enormous, there were large and small stones gathered around the construction site, sorted from their size.

She also noticed that her demons used magic, which surprised her a little because she didn't think she was giving them that function. The two golems, which were now more compact, took the smaller stones and used mana to change their shape, cut them or combine them with other stones. The wolves, which now had light fur from thin leaves, used magic to manipulate plants and wood as if it was their own body. The less impressive puppets used stone tools which were reinforced with magic to make details in the wood and did so pretty quickly with their three pairs of hands, their appearance has hardly changed except that a black stone appeared in the middle on their face.

"Well I did tell them to make a more pleasant place in here." Yui said to Miyu with an uneven tone, caused by a slight shock. The demons only noticed them for a moment and then returned to their work. "However, I did not expect them to be able to use magic."

"Well, they have strengthened themselves by being close to such a powerful source of mana, using magic is just another step in the evolution of the demon." Explained Vili, who together with the girls went under the tree and the girls sat on the furniture prepared for them. At that time, the plush demon turned into its more demonic form his body was covered with a shady fog that grew to reveal the result of his transformation. At that time, Vili flew up to the tree, picked off the amethyst fruit from it, and put it on the table showing it to girls who were still watching the working demons.

"Yui, Miyu look at this," She drew the girls attention to the fruit. "It's a magical fruit that can increase magic power. Unfortunately, it is immature and can only increase the magical power of demons."

"You know a lot about it," Yui noticed, and Miyu nodded to it. "Was there something similar in your world?"

"Yes, and in this world it will become natural in a few years time. Very rare, however still natural, the Earth simply hasn't soaked enough up mana yet. When that happens there will be many new species of plants and trees, such as this, that will be formed on magic points." Vili explained and then threw the fruit to the demon who ate it in one fell swoop.

It didn't take long to see him change, because his eyes were shining and he got an amethyst glow, which had a mystical effect. His fangs became longer and sharper, just like his claws. His body became even bigger leaving him unable to fit in Yui's house and he was surrounded now by a shady amethyst fog that held close to him, responding to his orders. After a while, the changes stopped appearing, and the demon just bowed down to his lady.

"Why don't you give him a name?" Miyu suggested, slowly approaching the wolf to stroke him, expecting his fur to be even nicer than before. Yui agreed with this proposal, after all, her demon was now quite a challenge Magical Girl of the second rank but she still thought he would lose in an equal fight.

"This is a good idea." Yui agreed and, without thinking too much about it, gave him the first name that came to her mind when she was thinking about the big wolf. "How does Fenrir sound?"

"It's from mythology, right?" Miyu asked, holding on to her chin, trying to remember where she heard the name. 

"Yes." Yui said simply, without paying too much attention to Miyu, because she was looking at Fenrir, whose eyes were shining when she gave him the name, gaining more intelligence and even some mana which Yui felt.

"Well, more demons should be made." Yui said and approached the Magic Tree, placing a hand on it, she started drawing mana to create magical cores which appeared in her free hand. The first ten were the size of tangerines meaning several of them fell to the ground, she also created five apple sized and two pineapple sized. The crystals themselves were transparent with shades of amethyst.

"This is all I can get out of the tree." Yui said and Vili nodded, then they all picked up the crystals and put them on the table. "For some reason they seem too clean to be artefacts."

"Probably because your power needs to have negative emotions to work, and it's pure mana with no extras." Vili explained.

"So what kind of demons will you make?" Miyu asked.

"Well, I had some ideas." Yui said, reaching for the bag that she brought with her with contained many items brought from her home.