Warning: Spoilers for Obi-Wan Kenobi episode 4.
Although the concept of a Force dyad was not introduced until Star Wars: The Rise of Skywalker, Obi-Wan Kenobi hinted that Obi-Wan and Anakin Skywalker may have formed a dyad long before then. Taking place ten years after Star Wars: Episode III — Revenge of the Sith, Obi-Wan Kenobi centers on Obi-Wan finally facing his past during his years in exile. Much of Obi-Wan’s regret stems from his failure to teach and protect Anakin. And, although the former master and apprentice had a close relationship, Obi-Wan could not prevent Anakin from falling to the dark side of the Force.
Near the end of Star Wars: The Rise of Skywalker, Emperor Palpatine discovered that Rey and Kylo Ren formed a Force dyad or a bond that made two Force-sensitive beings "one" in the Force. This connection gave its members unique abilities, including communicating from light-years apart, seeing and feeling each other’s experiences, and even power over life itself. Since Force dyads were incredibly rare, Emperor Palpatine was surprised to learn that Rey and Kylo Ren shared this bond, stating that a Force dyad had been “unseen for generations.”
Related: Genius Anakin & Padmé Force Dyad Theory Fixes Star Wars' Worst Death
However, Obi-Wan Kenobi implies that there may have been another Force dyad before Rey and Kylo Ren: Obi-Wan and Anakin. At the beginning of Obi-Wan Kenobi episode 4, Obi-Wan and Darth Vader were in bacta tanks for healing on separate planets. During this time, both experienced the same sensations and remembered the same points in their recent battle. In addition, earlier in Obi-Wan Kenobi, Vader reacted when Obi-Wan learned of Anakin’s fate and said his name aloud for the first time. This
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