The Force Dyad may have been first introduced in Star Wars Episode IX: The Rise of Skywalker, but light and dark sides - a perspective that KOTOR explored long before.
[Major spoilers for Knights of the Old Republic follow below.]
Set within the Legends branch of canon, KOTOR is set 4,000 years before the original Star Wars films. Darth Revan and his apprentice, Darth Malak - both former Jedi Knights who fought the Mandalorians prior - wage war with the Old Republic and lead a revitalized Sith Empire to many victories. A Jedi strike force led by Bastila Shan is sent to apprehend Revan and Malak, before a battle ensues with Malak betraying his Master. However, Bastila both heals a wounded Revan and temporarily erases his memories by the orders of the Jedi Council.
Revan and Bastila bond over the course of the game's story, and it's possible to interpret it as one of the first-ever Force Dyads. Revan has a unique experience, having been a Jedi and a Sith, meaning he maintains a more precarious balance between the light and dark, unlike other Jedi. Bastila Shan, conversely, remained a Jedi throughout KOTOR, but was enamored with not only Revan's comion and power, but also his focus on the Jedi code despite being a Sith prior.
Revan And Bastila Shan May Have Been A Force Dyad
Eventually, in KOTOR's story, both characters would feel a connection in each other and the Force, with Revan having frequent visions of Bastila's memories and the pair having shared dreams. Later in the game, Bastila is captured by Malak and falls to the dark side. Eventually, Revan redeems Bastila, a feat that is incredibly difficult to do and would be impossible if not for their bond. Their bond would naturally turn to love, and their descendants would feature as prominent characters in BioWare's KOTOR follow-up, The Old Republic MMO.
Revan's bond with Bastila is akin to that of Rey and Kylo Ren's, with both having experience with the dark and light sides of the Force. A balance is forged through shared trauma and hardship, and a Force Dyad is created, a more powerful bond than the Sith or Jedi were capable of alone. The bond allowed access to abilities that are on mythological levels even for Star Wars standards. The Rise of Skywalker unlocked access to Force Healing for Rey and Kylo Ren that inadvertently rejuvenated the Sith Eternal, Emperor Palpatine. In Star Wars: Knights of the Old Republic, it not only boosted Revan and Bastila's abilities to defeat the Sith Empire, but it opened a dialogue between the two sides during one of their most destructive conflicts.
