This is Genshin Impact.

Aether encounters losing his sister, taken away by a God who's unknown. He got teleported in a sea and he was fishing. He then fished a little girl who's height is 1.5-2ft. Aether pulls her out.

The girl says her name, Paimon. Paimon looks at Aether angrily but happy that she is finally out.

After a few months, 2 months past by and they walk around and they find Mondstadt.

Aether and Paimon was about to walk towards it as someone stops them. [insert character] (you) quickly stopped them.

"HEY!! DONT STOP US!!" Paimon yells annoyed.

"Paimon, stop yelling." Aether tells Paimon.