The fourth arc of A Certain Magical Index, consisting of volume 4 of the light novels and episodes 15-17 of the anime. This story arc was omitted from the manga for some reason, even through some important plot points happen here.
- Adapted Out: The portion of the Angel Fall investigation surrounding the serial killer, Hino Jinsaku, whom was believed to be the culprit that casted Angel Fall, was cut from the anime adaptation.
- A Day in the Limelight: For Kaori, Motoharu, and Touma's family.
- Arc Villain: A fallen angel naming itself Mishanote who takes the form of Sasha Kreutzev due to Angel Fall
- Barely-There Swimwear: The swimsuit Touma's mother wears.
- Brain Bleach/Fan Disservice: Seeing "Index" in such a scanty swimsuit and then "Pierce" in a girl's swimsuit.
- Can't Bathe Without a Weapon: Kaori carries her sword everywhere with her, even when she bathes.
- Contrived Coincidence: The Angel Fall spell was cast accidentally by Touma's father. Tsuchimikado notes that with the amount of occult artifacts he had collected, casting some spell was inevitable, and it's a miracle it was a relatively benign spell like Angel Fall.
- Godzilla Threshold: Gabriel is such a threat that Kaori reveals her magic name right away instead of as a last resort.
- The Greatest Story Never Told: Touma's ordeal through this entire arc is only known by Kaori and Motoharu.
- Mike Nelson, Destroyer of Worlds: Toya Kamijou almost caused the world to be destroyed, and he never learns this.
- Moment Killer: Touma intentionally stops his parents from having sex, since his mother looks like Index at the moment.
- Our Angels Are Different: This is the first story where we meet an angel, the titular creature that fell from Heaven due to the spell. While it attempts to return in a non-violent way, in the end it will have no choice but to cause massive destruction to fuel its re-ascent.
