MTL - Immortal Executioner (Zhanxian) - Chapter 1307 Good talking dragon (below)

A man is reborn into the world of Avatar: The Last Air Bender as a waterbender from Katara's tribe. Best of all, he was the same age as her, and he had a system with him to help.He knows the future and a system that lets him continuously get stronger by completing quests or long-term missions, as well as giving him the ability to copy abilities from others for himself. He will become invincible in the world of Avatar, even more so than the Avatar himself.

High-school student Koremitsu Akagi finds himself attending the funeral of Hikaru Mikado, who had died in an accident during Golden Week. He’s not sure why he’s there, as he only exchanged a few words with Hikaru at school. However, Hikaru doesn’t seem to be completely gone from the world, as he comes back as a ghost in order to fulfill a promise to Aoi Saotome, his fiancée. Since Koremitsu is the only one who can see him, he asks him to carry out his promise in his place.

Complying with his request, Koremitsu tries to fulfill Hikaru’s promises to the rest of his “girlfriends”, helping them overcome past misunderstandings and repair broken relationships.

What would happen, if one day fantasy collides with reality?

- Description from Novelupdates