The Twilight society are a group of Ponies residing within Tenpony Tower. They are a secret group of residents that protect the pre-war technology within Tenpony Tower, specifically technology Twilight herself had placed here. Littlepip calls them out on how they're not doing anything to help the wasteland and are no better than the Steel Rangers hoarding technology.
The Twilight society agrees to aid Littlepip after they see a set of memory orbs that she had recorded earlier. The Twilight society sends Life Bloom with Littlepip to assist on turning the Wonderbolts against the Enclave and their lies.
The Twilight society also particapates in the battle for Fillydelphia, where they deploy the megaspell Celestia One. Celestia One is used to launch precision strikes in Fillydelphia, destroying Enclave and Red Eye's forces. It is also implied that it was deployed near Spike's cave during the battle of Dragon Mountain.