Inner Demon — ruling 1

Inner Demon's triggered ability affects only non-Demon creatures on the battlefield at the time it resolves. Creatures that enter the battlefield later in the turn won't get -2/-2. Unless Inner Demon leaves the battlefield before that ability resolves, the enchanted creature won't get -2/-2.

Inner Demon : règles, fonctionnement et interactions (MTG)

Inner Demon is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Enchant creature Enchanted creature gets +2/+2, has flying, and is a Demon in addition to its other types. When this Aura enters, all non-Demon creatures get -2/-2 until end of turn.

How it works : Inner Demon

Original English text — Wizards of the Coast / Scryfall

#1June 8, 2018· Wizards of the Coast
Inner Demon's triggered ability affects only non-Demon creatures on the battlefield at the time it resolves. Creatures that enter the battlefield later in the turn won't get -2/-2. Unless Inner Demon leaves the battlefield before that ability resolves, the enchanted creature won't get -2/-2.
No other card is named in this ruling.