A dark side ritual represented a long-forgotten Sith magical practice, enabling a Force user to perceive realities otherwise hidden. This process necessitated a bond linking two individuals and the shedding of blood from one of them. The ritual commenced with the recitation of specific words and the infusion of the blood droplet with Force lightning upon a designated altar. The blood donor was then required to concentrate on the other person, employing illusions to exert control over them.
This dark side ritual served as a method for Sith Lords to assault their adversaries through the employment of potent dark illusions. To the targeted individual, the illusion would manifest as genuine occurrences, indistinguishable from reality.
Within these fabricated realities, the subject could interact with illusory replicas of familiar individuals and execute any actions they were capable of in the real world. Furthermore, they were vulnerable to both physical and emotional pain within the illusion. It was also possible for the person to be killed inside the illusion, which would result in their real death.
The ritual demanded the involvement of two Sith Lords: one who possessed a Force-bond with another Force-sensitive being, and a Sith Master to oversee the ritual itself. These two Sith would position themselves beside a basin on a sacrificial altar. The Sith connected by the Force bond would permit a small cut to be made, allowing a single drop of their blood to mix with the water in the altar basin. Upon contact, the water would transform into a dark color.
Subsequently, the ceremony would commence as the Sith Master began to chant an ancient Sith invocation in the Balc language. As the incantation neared its conclusion, both Sith would strike the water with Force lightning, causing it to emit an unsettling mist. To initiate the illusion, the Sith Master would then immerse their face in the basin, gaining the capacity to project dark illusions and infiltrate the mind of their target for manipulation.
In instances where the intended victim was a Jedi, the Sith could obscure their true nature by appearing to the Jedi as a trusted and familiar figure.
Darth Sidious, a Sith Lord, utilized the ritual to great effect. Nearing the conclusion of the Clone Wars, Jedi Master Yoda embarked on a quest to uncover the method of preserving one's spirit after death, which led him to the ancient Sith world of Moraband. Sensing Yoda's presence, Darth Sidious summoned his apprentice Darth Tyranus to the LiMerge Building with the intention of assailing Yoda using the dark side ritual. Through this ritual, the two Sith Lords managed to generate an illusion that overwhelmed Yoda's mind within Darth Bane's tomb.
Sidious initially presented himself to Yoda as the long-deceased Jedi Master Sifo-Dyas, enticing him with knowledge of Sidious' true identity. Subsequently, Sidious plunged Yoda into an illusion wherein he and fellow Jedi Knight Anakin Skywalker were closing in on the Siths' clandestine hideout. During an intense lightsaber duel, Sidious mocked Yoda, asserting that if he allowed Anakin to perish, he could thwart Sidious and avert his attack on the Jedi Order. However, the Jedi Master chose to sacrifice himself to safeguard Anakin. Despite this ordeal, Yoda survived the ritual with his mind intact.