|Defender of All Universes|
|Air date||June 15, 2018|
An epic battle leaves the universe in a state of chaos, threatening to destroy all life unless a sacrifice is made.
Keith sends the Shiro clone to the Castle of Lions while Voltron engages Lotor's mech. Lotor begins the battle by firing a massive energy beam. However, Voltron forms its shield to protect itself from the beam, but it pinned down. Keith order Hunk to create the shoulder cannon and Voltron fires at Lotor. Unfortunately, Lotor's mech is far too fast and avoids shoot with incredible speed. The Paladins decide that the best way to fight Lotor is in close quarters combat forms Voltron's sword.
Meanwhile, Lotor's mech brandishes a pair of twin scimitars and charges at Voltron. The two mechs engage in a fierce clash of blades with Lotor prompting a challenge of Alfor's legacy (Voltron) against him as the new Altean defender. Voltron and Lotor's mech continue to fight, but Voltron is barely able to defend against the mech's speed and ferocity in battle. Hunk suggests that they back Lotor into a corner, and Voltron flies over to a lone asteroid. Lotor gives chase and fires at Voltron upon reaching the asteroid. The Paladins defend themselves with Voltron's shield as Lotor continues to fire at them. Lotor is unable to make a direct hit and charges Voltron head-on with its scimitar at the ready. At the last second, Voltron flies out of the way and leaves Lotor to slam hard on to the asteroid. Voltron immediately approaches Lotor and fires its laser, blasting against the asteroid. Lotor is unable to escape and is seemingly blasted through, but is discovered to have fled in time. The Paladins once again fire with Voltron's shoulder cannon, but Lotor suddenly disappears. The Paladins are uncertain of what just happened, and Lotor reappears out of thin air and strikes Voltron. Back at the Castle, Shiro's clone is being watched by Coran and Krolia.
At the battle, Lotor warps in and out of reality, continuously hammering Voltron with an onslaught of attacks. Allura quickly deduces that Lotor's mech is able to jump into the Quintessence field without the aid of the gate, all thanks to her giving his ships the ability to do so. Lotor basks in the newfound power of the Quintessence, seeking to use to ruler over all realities in his new Altean empire, and strikes Voltron with a massive energy beam. The blast knocks Voltron down, and Lotor warps into the Quintessence field. Keith says they have gain power from the Quintessence field to match Lotor's strength. Despite a hint of doubt, Allura agrees to open a rift in the field with the aid of the other Paladins. The Paladins focus their energy, and a rift to the field is created. Voltron then forms its Blazing Sword and plunges it into the breach, creating a path in the Quintessence field to face Lotor.
In the field, Voltron and Lotor's mech fight again, but this time on level playing-field; they clash with their swords and are evenly matched. The Paladins discover that the energy in the field is empowering Voltron, making it easier to fight Lotor with Keith adding that Voltron is capable of more than what they know. With the newfound power surging through them and their lions, the Paladins attack with great fury. Voltron and the Lotor's mech battle with high intensity, clashing their blades as they fly, even to the point where they can't be seen. The Paladins and Lotor become more aggressive as the battle rages, and the Paladins manage to force Lotor back. Upon hearing her fellow Paladins' declaration to destroy Lotor once and for all, Allura realizes that the Quintessence is corrupting them the same way it did for Zarkon and Honerva, says that they need to get out of it. However, Lotor has already succumbed to the madness and declares Allura weak for being afraid to use the power of the Quintessence. The Paladins try to retreat, but Lotor still wants to fight and chases after them. Hunk question how they stop the fight and Allura says to give all the power to Lotor. Allura then uses her alchemy to purge Voltron of its excess Quintessence and funnel it into Lotor's mech. The energy drives Lotor mad, but he charges ahead to Voltron, roaring in rage and refusal to be defeated. The energy is taking a toll on the Paladins' lions, overloading their systems. Voltron continues to give its Quintessence, and Lotor fights on to reach it. With a final blast, Voltron unleashes all of its energy to Lotor's mech, overloading and disabling it, and leaving Lotor incapacitated. The Paladins then escape the field and leave Lotor to his fate.
Now back into space, the Paladins receive a warning from Coran who discovers that Lotor's constant jumping in and out of the Quintessence field has caused numerous rifts in reality that, if unchecked, would destroy the universe. He believes that overloading the teludav would seal the rifts, but the at would destroy the Castle in the process. The Castle is evacuated and then enters the rift; the teludav overloads and explodes, closing the rifts. In the aftermath, a single diamond is formed.
Landing on a small planet, the Paladins try to help Shiro regain his spirit. Using her powers, Allura manages to extract Shiro's spirit from the Black Lion and transfers it into the clone body. Shiro is revived, but as a result, all of his hair turns white. Wondering what to do next, Pidge reveals that she gave a copy of the Castle's schematics to her father when he left for Earth. Keith then declares that they are finally going home.
- Space Mice
- Kaltenecker the Cow
"Good-bye, old friend."
— Coran saying his last goodbye to the castle
"You found me."
— Shiro, after coming back to life
"We're going home."
- Lacey Chabert voices Romelle instead of Mimi Davila, who was unavailable for this episode.
- The Quintessence was funneled through the golden V-shape in Voltron's chest, much as power was drawn through the original Voltron's Electro-Force Cross.