Zhi You Wo Neng Yong Zhao Huan Shu

When Zhang Ze transmigrated to a parallel world where people fought monsters in the magical realms in order to gain strength and protect against monster invasion. For the sake of his sister, Zhang Ze entered the magical realm and took the name Luo Sha, and accidentally gained the strongest SSS skill of Summoning! He could summon any monsters he killed, and the higher his Summoning level, the more monsters he could summon. As he gained levels, he became invincible!

(Source: Kuaikan, translated)