This was an anime called Mecha Beast God. Mecha Beast God was a manga series created by Japanese manga artist Yoshihiro Tomika, which was released in September 2015. The story was about the protagonist, Xiao Chun, who accidentally traveled to a foreign world full of mecha and magic during an adventure. She met an old mecha beast,"Gust", who needed to evolve into a powerful robot beast to protect the world. With the help of Haru, Gust evolved into a powerful robot beast and started an adventure to protect the world with Haru. During this process, Xiao Chun and Gu Site gradually developed feelings for each other.