|The Black Paladins|
|Air date||June 15, 2018|
As one Paladin takes on a dangerous mission through a wormhole, the others contend with failing controls on the castle.
With Keith back in command of the Black Lion, the Paladins engage the Sincline ships in battle. The ships are piloted by Lotor's generals, and as the battle continues, Shiro escapes with Lotor. The enemy escapes through a wormhole created by Honerva, although Keith manages to make it through the wormhole at the last moment.
Shiro delivers Lotor to his generals, and Honerva then orders Shiro to draw Keith away. As Lotor awakens, Honerva reveals that she is his mother, but Lotor cannot accept it and refuses to acknowledge her as his mother. After that, Honerva orders Acxa to take him away but she betrays her by attempting to stun her with her gun, however Honerva escapes by disappearing. Soon after, it is revealed that Acxa has been working with Lotor the entire time so that Lotor would earn the Paladins' trust; Zethrid and Ezor reaffirm their allegiance to Lotor. They take the Sincline ships and head for the Castle of Lions.
Meanwhile, the Castle is suffering the effects of a virus planted by Shiro. All systems are shut down, leaving the Castle powerless. Pidge has to come with terms with what Shiro just did and has to reveal the fact apart of her had planned for that very outcome. Shiro leads Keith to a secret facility where Keith discovers a host of Shiro clones. Shiro and Keith fight – Keith is scarred in the battle, but manages to cut off Shiro's artificial arm. As the facility is destroyed around them, Keith tries to rescue Shiro, remembering how Shiro promised to never give up on Keith.
"Shiro, I know you're in there! You made a promise once. You told me you'd never give up on me!"
"And I should have abandoned you just like your parents did! They saw that you were broken. Worthless. I should have seen it, too."
— Keith vs. Shiro
"Shiro, please! You're my brother! I love you!"
— Keith to Shiro
- Shiro seemingly betrays his closet friends and plants a kill virus in the Castle and tries to kill Keith.
- Keith realizes this "Shiro" is a clone.
- Pidge struggles to stop the castle from exploding.
- Much of the animation from Mir came back below standard and had to be fixed "in-house", with much fixing done by Kihyun Ryu, leading to the heavily stylized and detailed scenes.
- The struggle in the Castle of Lions was originally a longer scene depicting the characters shutting off switches in various rooms, but it was ultimately condensed into Pidge's significant foresight.
- The addition of the Lions having power cores was added in for plot purposes to create drama and separate Keith from the team, not something conceptualized for the Lions beforehand.
- Staff attributes Keith's inner turmoil of fighting against someone who is not truly evil as the push that brought out his Galra features.