By the Grace of the Gods (Manga) 13

Slime's up for one recently deceased middle-aged businessman! When the gods reincarnate him in another world as a boy with magical powers, he discovers that magically tamed slime are an untapped natural resource! The founding festival brings great joy to Ryoma and his employees as they enjoy all that the festival has to offer. Basking in the warmth of his friends during the festivities, Ryoma feels great gratitude toward his second chance at life. After the festival comes to an end, Ryoma turns his focus to his main goal of raising his level as an adventurer to make the journey through the Surrus Jungle. Luckily, the guild master of the Adventurers' Guild gives him a job hunting treants, a plant-type monster similar to what can be found in the Surrus Jungle. Hunting treants is perfect practice to prepare for Ryoma's journey, but the practice becomes perilous when an elder treant makes an appearance!