The Forbidden Forms represent specific styles of lightsaber combat that were employed by the Sith throughout the duration of the Sith Wars. The Jedi Cervil the Uncanny testified that lightwhips—a flexible-bladed variation of the standard lightsaber—served as a defensive measure against Sith Lords who practiced these unique combat forms. During the High Republic Era, specifically in 232 BBY, Jedi Knight Vernestra Rwoh, while marooned on the jungle moon of Wevo, referenced the accounts of Cervil the Uncanny concerning the Forbidden Forms. This occurred during a discussion with her Padawan Imri Cantaros, who had voiced reservations regarding her alterations to her lightsaber, which enabled it to function as a lightwhip.
The junior novel The High Republic: A Test of Courage, authored by Justina Ireland in 2021, contains references to the Forbidden Forms. This novel is a component of Phase I of the comprehensive Star Wars: The High Republic multimedia initiative.