What brought Roshi a turn for the better was a crystalline substance called the 'Black Devil'.

This is not a natural material ore, but a crystalline structure produced by the combustion of a special liquid called 'devil's blood'.

The liquid is oily, which looks a bit like oil, and it is also a mineral buried deep in the ground, which is also flammable, but not as viscous as oil and has a higher ignition point.

Roshi found that when they burned, they left behind some crystalline solids, which unexpectedly had more than twice the elemental content of gold coins.

Roshi thought about it for a while, and felt that it was very feasible to replace gold coins with this kind of thing, after all, from the available information, its mine reserves were no less than the oil on the earth.

The only problem is that no one has discovered and used this kind of thing in this era, and it is more troublesome for Roshi to obtain these burned crystals.

But after thinking about it carefully, Roshi felt that this problem might not be a big deal.

As a visitor to Earth, Roshi knew that the value of this kind of thing was definitely very huge, as long as he made something casually and threw it into the mortal world to slowly take root and sprout.

For more than ten years in the mortal world, a wizard is just a time of retreat, and by the time his retreat is over, this thing is estimated to have become popular.

After thinking about it, Roshi finally settled on the kerosene lamp, which is the easiest to popularize, because this thing is simple to make and relatively easy to popularize.

After making the decision, Roshi began to take action, buying a series of lampshades, handles, gauze, and other tools needed in the production process.

In fact, Roshi has always felt strange about the industry of this world.

Whether it is in the Dragon Wing Continent or the Northland Continent, it seems to be in the fifteenth or sixteenth century of Western Europe, but there are always something more advanced than this era.

For example, very advanced and sophisticated mechanical clocks and pianos, and when he was in the Black Tower, Roshi even saw a wizard's laboratory with a very steampunk appearance, and even some wizards, who were not dressed like the culture of this era.

Roshi had discussed these novelties with Louis, and the reply they received was that they were all from wizards, like the nautical instruments on the Tulip.

It's just that Roshi has been in the Black Tower for so long, and he hasn't found any wizards who are obsessed with inventions, and they don't look like such an open-minded group.

A simple kerosene lamp is made by combining a lampshade in the shape of a thin gourd with a cross-shaped wire, placing them on an iron vessel loaded with the blood of the devil, and finally pressing the wick and attaching the handle, and a simple kerosene lamp is made, which is undoubtedly much more clever than old lighting tools such as torches, both from the perspective of safety and brightness.

Then, Roch wrote a letter himself, which explained in detail the purpose of the kerosene lamp, as well as the so-called blood of the devil, and provided some subsequent development directions and application ideas, and went out with the small lantern.

Far from the war, Rogue is a very laid-back town.

It was autumn, and the cool autumn wind blew through the golden wheat fields into the town, and the windmills above the mill followed the black twist and turn.

The townsfolk lined up with burlap sacks under the mill, and the children, mostly barefoot, laughed and played in the streets, kicking up a cloud of dust as they ran, and from time to time there was a burst of pleasant laughter.

They are all relatively simple and enthusiastic, and most of them will come to say hello when they see Roshi.

Roshi was not very popular when he first arrived, after all, the homeless man is not synonymous with good in this world, sloppy, dirty, unhygienic, scoundrels, etc.

It's just that after a long time, everyone found that this old man who lived alone was different from other homeless people, and he would not take the initiative to ask for food or anything like that when he was stuffed in the hut every day.

This aroused everyone's sympathy, and recently this week, some townspeople often came to visit him, bringing him some vegetables and food, and for fear of hurting Roshi's self-esteem, they basically left something and left, and never asked about his past.

Anyway, after everyone comes into contact, this old man's image and temperament are not related to the homeless man, and he is still single at this age, so there must be a reason for it.

While walking through a grain pile, a group of children are playing games next to the grain pile, and Roshi sees Christina inside at a glance.

Today, she wears a beige floral dress, her flaxen-colored hair is braided into several tiny braids, which are coiled on the top of her head, and her fair skin is like a porcelain doll.

"Christina, are you playing?" Roshi greeted warmly, Christina's parents came to visit him, and thanked Roshi for saving Christina, the child didn't know what happened that day, but the adult understood what would happen without Roshi.

After shouting and not hearing a response, Roshi thought she hadn't heard, and raised her voice a little more, "Christina, what are you playing?

Roshi was sure that Christina heard it this time, because the children next to her noticed Roshi, and several older boys whistled with a bit of teasing.

"Christina, your knight called you!"

"Christina, be a bride!"

"Marry the knight who saved her, and live in a great palace. ”

"Hey, where is the palace? Isn't it a haunted house?"

The children's ridicule of Roshi realized what was going on, most likely because his glorious deeds were publicized, and the town kids nested some fiction stories into it, and Christina's subsequent reaction confirmed Roshi's suspicions.

Under the coaxing of the children, Christina's porcelain doll-like face became redder and redder, and soon she turned her head like a fever, and glared at Roshi angrily.

"Ugly, I don't want to play with you!"

Dropping this sentence, she ran away with a group of children next to her, leaving Roshi standing alone in place.

Luo Xi raised his dry palm and touched his old face, the rough touch between the centipede-like wrinkles and the friction of his palm was indeed not very pleasant.

It's just that...

Don't you want to be so direct...

Hurt self-esteem...