Despite being the same race, there are many differences between Odo (René Auberjonois) from Star Trek: Deep Space Nine and the Changeling villains in Star Trek: Picard season 3. In deciding to use the Changelings as season 3's main villain, Picard brought back one of classic Star Trek's most important races, updating their history and lore in the process. First introduced in Deep Space Nine, the Changeling race has a long and complex history in the franchise, mainly explored through the character of Odo.
Odo was part of the main cast of Star Trek: Deep Space Nine and he discovered he was a Changeling at the beginning of season 3. For much of the series, Odo was at odds with his fellow Changelings because of the Dominion War but was eventually instrumental in ending the war and returning to his people. Since the end of Deep Space Nine, the fate of the Changelings has been mostly unknown, but Star Trek: Picard season 3 revealed that there had been a schism within their society and that a rogue group including the season's villain Vadic (Amanda Plummer) had left in order to mount another attack on the Federation.
