Heartless Angel

Heartless Angel, also known as Fallen One, is a recurring enemy ability in the Final Fantasy series. When used, it brings the party's HP down to 1. Though it did not first appear in Final Fantasy VII, it has become a signature attack of sorts for Sephiroth.

Final Fantasy VI
Originally translated as Fallen One in the SNES version, Heartless Angel reduces all opponents' HP to 1. The attack depicts angels coming down from above, dealing damage. Kefka Palazzo uses this in the final battle (he is also the only non-dragon enemy to use it), but the Kaiser Dragon, Fiend Dragon, Holy Dragon, and Crystal Dragon also sport this attack.

Final Fantasy VII
In Final Fantasy VII, Heartless Angel is only cast in the final battle by Bizarro∙Sephiroth and Safer∙Sephiroth. It takes the form of a single angel that sprinkles deadly magic on your characters.

Crisis Core -Final Fantasy VII-
Sephiroth uses Heartless Angel during his first battle with Zack Fair. Professor Hojo's simulations of Sephiroth, Experiments No.'s 107, 108, and 124 also use the attack.

Dissidia Final Fantasy
In Dissidia Final Fantasy, Sephiroth can use Heartless Angel during his EX Mode. The attack will reduce the opponent's Brave to 1.

Kingdom Hearts
This attack returns prominently in both of Sephiroth's boss battles in the Kingdom Hearts series. This time the attack can be stopped if the player is quick enough, but if they fail it will sap their HP to one and completely drain their MP to zero. One of the most effective ways of recovering from being hit with this is to use an Elixir or, if you lack one, other healing items, preferably used in rapid succession.