Immortal Fire is one of Agni's unique transcendental skills that allows him to relocate to anywhere there is an active flame or fire. It is just like teleportation, except for the fact that there must be fire at his destination.
Agni can move as far as his summoners vigor allows far beyond his line of sight , so if he gets caught in a difficult situation, he can move very far away and regenerate, thus the name Immortal Fire. However, the greater the distance traveled, the more difficult it is on his summoner. Since the distance depends on the amount of vigor the summoner has left, he is careful not to overuse this skill. Therefore, Agni tries to get an idea of how far he can move with this skill, based on his summoner's vigor, before he must resort to other transcendental skills in order to avoid reducing his summoner's lifespan.
During the times when Agni was able to use this skill on his own without the limitations of a summoner, he was one of the gods who could move among the stars the quickest.
Agni uses this transcendental multiple times in the webtoon.
- Near the end of the attack on Atera, Agni uses this skill on the resulting fires from his earlier use of Nine Snakes of Hell as he searches for Sagara.
- Agni uses this skill to travel quickly from Atera to Kalibloom, where Gandharva is rampaging in his sura form. He appears in a fire at the Temple of Earth that someone was in the process of putting out.
- Agni uses this skill again to travel quickly from Atera to Kalibloom, where Gandharva and Maruna were sighted. Since Chandra turned off all the fires in the city in order to stall him, Agni appears in a torch carried by a reformed thief outside the city.
- several other times