After Si'er went downstairs, she habitually went to see her second brother first. Ever since the Zerg became able to reproduce, Si Xu had started researching sterilization potions.

In addition to sterilization agents, he also developed many egg-killing sprays. With just a light spray, a bunch of insect eggs can instantly turn into sewage.

Killing only the eggs is not enough; the adult Zerg should also be killed! So Si Xu developed many insecticides.

Although Si Xu was very confident in his alchemy skills, he would always ask Jun Bai to deliver the potions to Bei Ye City after he finished making them, so that Yu Bei Ming could hand them over to Yu Bei Xuan.

The potion processed by Yu Beixuan was truly deadly. Not only was its lethality hundreds of times greater than before, but no one could develop an antidote. It could kill the Zerg in agony every time.

After developing several good prescriptions, Si Xu made all of these insecticide prescriptions public for free, allowing all pharmacists to join the insecticide team.

Those who had some connection with the Yu family would ask someone to have Yu Beixuan process their work.

For the sake of human stability and the extinction of the insectoid race, Yu Beixuan never refused any offer. As soon as he emerged from seclusion, he would pour all the negative energy within him into those potions.

Not only does he know how to process things, but Tun Tun and Yu Bei Gui also like to help with the processing.

After the triple poison, almost all the Zerg ran away at the sight of the alchemist, and not a single one dared to confront him head-on.

Previously, they always thought that apothecaries were easy targets, the pushovers among humans. But ever since all the apothecaries started researching insecticides, the pushovers have become like a big durian—heavy, hard, and thorny, making them unbearable for the humans.

When Si Er entered the pharmacy, he saw Si Xu fully armed and researching insecticides. There were also several large cages in the pharmacy, all of which contained live insects captured by the Si family for Si Xu's research.

Si Xu was very happy to see Si Er coming over: "Er Er, you're here? Go and rest for a while. Your second brother will come to see you when he's done with his work."

Si Xu hoped that Si Er could leave as soon as possible. He felt that the scene of him injecting the new medicine into the Zerg later would be rather unseemly, and he didn't want Si Er to see it.

Si Er smiled and said, "Second Brother should also take care of his health."

“I cultivate upstairs during the day and only when the moonlight or starlight is strong at night, unlike my second brother who is often busy for several days at a time and forgets to eat and sleep. That is not good for his health.”

Si Xu chuckled and said, "What's there to worry about? Don't I have a soul pet by my side that can help with the healing?"

"With them around, they always help me regain my energy in time, so you don't need to worry about these things."

"By the way, my older brother is back today. Do you want to go see him first? I'll be there in a bit."

Si Er nodded upon hearing this: "Alright, then I'll go check on my older brother first."

Si Er quickly went to Si Yi's room and saw Si Yi's soul pets lying obediently in a row. Si Yi then took medicine and spirit fruit and fed them to the soul pets one by one.

"Big brother, are Little Fire and Little Flame injured?"

Si Yi smiled and said, "No, don't worry, they're all fine."

"However, after killing insects on the front lines for more than half a month, they were all exhausted."

The little golden crow flapped its wings and flew to Si Er: "Not only are our bodies exhausted, but our spirits have also been severely damaged. We need to replenish ourselves."