Shiro loves Keith. It's a fact of his universe. He loved Keith in the Garrison. When they spent long hours staring up at the stars, dreaming of the day they'd be among them. He loved Keith during the months flying to Kerberos, only Holts and pre-recorded messages to keep him company. He held onto that love as the arena broke him down body and soul. When they were reunited and fought together as Paladins of Voltron, that love flourished. Now as Haggar removed the scales from his eyes and he took his proper place as a servant of Emperor Zarkon, he still loved Keith. Even though the Red Paladin was misguided and stood against the one true ruler of the universe, the Champion loved him anyways. Lord Zarkon, in his infinite wisdom and mercy, saw this and granted his loyal follower's wish to show Keith the way or at least to keep him from trouble. He loved Keith, and he would keep him safe. Even from himself…
Keith is angry when they bring him to the Champion's quarters. He's been stripped of his bayard and outer armor. Left in nothing but the thin layer of cloth beneath. His arms are bound wrist to elbow behind his back. It leaves him unable to defend himself, when a particularly biting comment against the Emperor's good name prompts one of the guards to silence him with the butt of his gun. Shiro's snarl causes both the guards to snap to attention, saluting as he stalks over to them. He makes sure the senior of the two looks him in the eyes and sees his displeasure before he growls at them to leave.
He will have to send notice to any future escorts of the Red Paladin. Force is only to be used to prevent his escape or with explicit permission from the Champion. Keith will be brought to heel. He will be made to understand his new position in the world. What will and will not be tolerated, but he was a gift from the Emperor to his Champion. Disciplining Keith is Shiro's right and his right alone, until Lord Zarkon says otherwise.
"Shiro?" Keith's soft worried voice distracts him from the backs of the retreating guards, "Oh God, what did they do to you?" Shiro doesn't have to think to know what Keith is referring to. Since Haggar freed him from his misconceptions, his eyes have shifted to the Galra yellow. He might have been disturbed by it once, but now the sight stirs no feelings in him.
He smiles softly down at his gift, reaching out to pet his hair, "They've shown me the truth." He says simply. The fear that flashes across Keith face is rather cute.