Ahsoka viewers were left shocked at the end of the series' fourth episode, when Ahsoka found herself once again in the World Between Worlds. This mysterious, ethereal realm was first introduced on Star Wars Rebels, which saw Ezra Bridger access it via the Jedi Temple on Lothal. Rebels revealed that the World Between Worlds existed beyond the confines of time and space. While here, Ezra was able to reach into the past to save Ahsoka's life during her duel with Darth Vader on Malachor. However, the exact nature of this strange domain is yet to be revealed.
Source：https://www.cbr.com/what-ahsoka-reveals-world-between-worlds/
