Neo Bahamut (バハムート改, Bahamūto Kai?, lit. Revised Bahamut), also known as Bahamut Arisen, is a recurring creature in the Final Fantasy series, first appearing in Final Fantasy VII. It is a stronger red version of Bahamut whose signature attack is Gigaflare.
Appearances
Final Fantasy VII

Neo Bahamut appears as a summon materia obtained in the Whirlwind Maze, where it is permanently missable as the Maze is unrevisitable. It uses Giga Flare when summoned, dealing piercing non-elemental damage to the enemy party equal to 5x the base magic damage. If the party has obtained both the Bahamut and Neo Bahamut materias, they can later obtain the Bahamut ZERO materia from the blue Huge Materia.
Final Fantasy VII Rebirth

Bahamut Arisen appears as a summoning materia obtained by defeating it as a boss in Chadley's VR simulator, first available upon reaching the Cosmo Region in chapter 10. The player can unlock weaker versions of the boss by analyzing summoning crystals in the Cosmo Region as part of World Intel, while also strengthening the summoning materia.
Final Fantasy Type-0

Neo Bahamut appears as a Bahamut-class eidolon obtained by completing the Expert Trial "Colonel Faith's Revolt" on Agito difficulty. It uses Rush, Giga Flare, and Shock Wave. Its summoning radius is 3,0m and its summon time is 35s-50s. While more powerful than the baseline Bahamut, its shorter duration may be a hindrance.
Final Fantasy Dimensions II
In the original free-to-play version of the game, Neo Bahamut from Final Fantasy VII/Record Keeper appeared as the main raid boss as part of the "Bahamut in the Abyss" Record Keeper collaboration event. Like other raid events, the encounter with Neo Bahamut had a twelve turn limit to be defeated. Neo Bahamut was removed in the premium versions of the game.
Dissidia Final Fantasy Opera Omnia

Neo Bahamut appears as a boss.
Pictlogica Final Fantasy

Neo Bahamut from Final Fantasy VII appears as a summon.
Final Fantasy Airborne Brigade

Neo Bahamut appears during Cloud's Giga Flare UR Legend summon.
Final Fantasy Record Keeper

Neo Bahamut from Final Fantasy VII appears as a summoning ability acquired by defeating it as a boss in the Nightmare Dungeon. The player is penalized for striking Neo Bahamut with Black Magic or physical blows, and it counters damaging Soul Breaks. Characters with access to 5★ summoning abilities have synergy when challenging Neo Bahamut, and defeating it upgrades their summoning ability to 6★.
When obtained as a summon, Neo Bahamut is a 6★ summoning ability that deals four non-elemental summon magic hits to all enemies. The player can only acquire one copy of Neo Bahamut, as the Record Crystal needed to craft it is a unique item won from the Nightmare Dungeon and used up in the crafting. If they shatter their copy of Neo Bahamut, they will regain the Record Crystal, allowing them to recraft it later.
Mobius Final Fantasy

The Final Fantasy VII incarnation of Neo Bahamut appeared as a light-elemental Mage ability card for players to summon during the Final Fantasy VII collaboration events. It allowed player characters to perform the Shinega Impulse (セインガインパルス, Sainga Inparusu?) ability, which dealt light-elemental damage within an area of effect and lowered their Break defense.
Merchandise
Neo Bahamut has been released as small trade figurines in Japan as part of Final Fantasy Creatures collections.
Etymology
Neo is a prefix from the ancient Greek word for "new" or "young".
Bahamut (Arabic بهموت Bahamūt) originated as an enormous whale in ancient pre-Islamic Arabian mythology. Upon Bahamut's back stands a bull with four thousand eyes, ears, noses, mouths, tongues and feet called Kujuta (also spelled "Kuyutha") (compared with the pair of Behemoth and Leviathan). Between each of these is a distance of a 500-year journey. On the back of Kujuta is a mountain of ruby. Atop this mountain is an angel who carries six hells, earth, and seven heavens on its shoulders.
Another version of the Arabic story is that Bahamut is indeed a dragon and he stands on a whale called Liwash.
In modern times, the game Dungeons & Dragons is responsible for reimagining Bahamut as the king of dragons, a benevolent Platinum Dragon; the opposite of the malevolent Tiamat, the five-headed Chromatic Queen of Dragons.
改 (Kai?) means "improved". In Neo Bahamut's Japanese name, it comes from Ki-202 Shūsui Kai (秋水改), a Japanese fighter plane.