The Six aren’t the only Astrals players can summon in Final Fantasy XV as players have also the option to summon a rather unique one, the Carbuncle. Noctis can summon Carbuncle during combat to revive and heal Noctis as well as all his companions.
Unlike the other summons, Carbuncle actually requires some work outside the game as well. Currently the only known way to summon it is by first playing the Platinum Demo available for free on Xbox/PS store. The demo, which features a prologue to the game is available on both consoles till the end of the year so players still have enough time.
While playing through the Platinum Demo, the Carbuncle will lead Noctis through the dream and help him defeat the boss at the end. Players can even rename it to their liking once the demo has been completed. After completing the demo, players need to launch the main Final Fantasy XV game where they will get a chance to recruit Carbuncle.
During combat, Carbuncle gets summoned automatically instead of having to press down L2/LT in the case of other summons. Whenever Noctis’ health goes down really low and is on the verge of dying, he will kneel on the ground and automatically summon Carbuncle which will heal Noctis and the other party members.
However, this can happen only once per battle so players can continuously rely on it if the battle is too much for them to handle. It should also be noted that this happens only in easy mode of the game and if players die in the normal mode, they will have to restart from a previous save point as the Carbuncle won’t be able to help them.