Warning: Contains SPOILERS for Mufasa: The Lion King!
Mufasa: The Lion King expands the story of the titular Lion King, but also completely changes a moment from 2019's Scar and Sarabi The Lion King redo. Mufasa and Scar's backstories before the events of The Lion King have always been mysterious, with vague lines being our only hints as to what happened before Simba's time. However, now that Mufasa: The Lion King finally expanded the stories of these characters, a The Lion King line is now much more moving.
Although it has always been known that Scar is jealous of Mufasa in The Lion King, Mufasa: The Lion King finally reveals why. It turns out that Mufasa is Scar's adoptive brother, who was once known as Taka. The duo became inseparable brothers who traveled together after their family was killed, meeting Sarabi, Rafiki and several others. The Lion King characters along the way. However, Sarabi is at the center of the fight between Mufasa and Takawith her leading to the creation of Scar.
Scar mentioned that Sarabi chose Mufasa over him in 2019's The Lion King
Foreshadowing this Mufasa reveal
Sarabi, Scar and Mufasa's wife, interact very little in both versions of The Lion Kingwith them only actually talking after Scar takes down the Pride Lands near the end of the film. The dialogue that exists doesn't reveal much, with them only exchanging a few lines. However, at one point, Scar says the phrase “A long time ago you chose Mufasa over me”, a phrase that gained much more meaning after the release of Mufasa: The Lion King.
Mufasa: The Lion King reveals that Scar actually loved Sarabi, with Mufasa even helping Scar in his attempts to woo her. However, Sarabi eventually falls in love with Mufasa, with the two ending up together while Scar becomes an outcast in the Pride Lands. Scar sees Mufasa's relationship with Sarabi as a betrayal, which is what makes Scar alert the white lions to Mufasa's location, starting the rivalry.
Scar's love for Sarabi in Mufasa adds an element of heartbreak to 2019's The Lion King
Making Scar a more sympathetic villain
Scar's love for Sarabi which is revealed in Mufasa: The Lion King completely changes the 2019 remake, adding an element of heartbreak to the story of The Lion King. After seeing the prequel, we now know that Scar doesn't just want power. Instead, he's also trying to win Sarabi back, with the villain claiming the love of his life alongside his throne.
While Scar is still wrong in The Lion King, Mufasa: The Lion King at least it tries to make him a more sympathetic antagonist. The line Scar says to Sarabi in the 2019 film is a reminder of his heartbreak, further cementing the tragedy behind his character. So while Scar and Sarabi still don't have much screentime together in The Lion King, Mufasa: The Lion King it makes watch time that much more impactful.