It has innate Undead status, even though it does not appear to be an undead creature. Red Dragons have valuable Flame Rings as their rare steal, which are otherwise only purchasable for 50,000 Gil in Istory or the Phantom Village.
As Red Dragons are undead, casting Level 5 Death on it will only cause it to regenerate. As they are, however, controllable, the player may give them Reflect status to learn Level 3 Flare, which can be used to destroy it on future encounters.
The Red Dragon can be fought in the Barrier Tower as a monster-in-a-box on two occasions: one can be fought for the Blood Sword, and another for the Gold Hairpin, although it is also possible to encounter two Yellow Dragons instead. These battles are the earliest opportunity to obtain Level 3 Flare, and a good opportunity to try and steal a Flame Ring. It takes some preparation to reap the full rewards of the battle, however, since Level 3 Flare must be reflected to be cast on the party, and the player cannot normally yet cast the Reflect spell, the Chemist'sMix ability Dragon Defense, using a Phoenix Down and Dragon Fang, must be used on the Red Dragon in its place. Second, the player must have someone to control the Red Dragon, someone who can steal the Flame Ring, someone whose level is a multiple of three and can learn Level 3 Flare, and someone who can cast the Time MagicReturn in case a Hi-Potion is stolen instead of the Flame Ring. Lastly, since the reflected spell only hits a single random party member, it may take several turns to hit the intended target. If no party members have levels multiple of three, it is sometimes possible to use Dark Spark to reduce their level such it becomes a multiple of three.
To defeat the Red Dragon, there are several efficient methods available. Controlling it and having it use Level 3 Flare against itself will kill it in four castings. Since it is weak against Earth-elemental attacks, summoningTitan with an Earth-enhancingGaia Gear equipped will deal around 4,000 damage.