Keith is the leader of the Paladins, as per Shiro's dying wish.
he hears the sound of his team in disarray in the background. it's common. Keith doesn't have the patience to calm them down anymore.
They've crash landed onto a ruined planet after flying through a wormhole in escape from the Galra empire. A strange planet where time doesn't seem to flow natively. Time is broken here.
They can no longer form Voltron. Neither Lance nor Allura can pilot Red. Black barely accepts _Keith_, and he doesn't blame it. It's been over a month. He's still grieving. No matter how hard he tries to clear his mind, to just think about the future--the missions, steps at a time to take back the universe from the hands of his own father, his head won't clear. He can hide his ears, eyes, skin, and claws. His team may accept him regardless of him being half Galra, but the way people who they've tried to save look at him now when he's even partially transformed is filled with a fear that makes him sick to his stomach.
Shiro was not there when Zarkon realized who Keith was, and laughed at Keith for rebelling and taking human form. Thace told him that he had been trying to find Keith since he left Keith, or rather, Lotor, stranded on earth.
Shiro was not there. He's six feet below the ground of a planet the Galra have since retaken from them.

Coran knows this planet. He was there when Alfor spoke in transmission with the time council that ruled this planet, before they found refuge for some of its people.

 after another failed mission has the technology to send peoples' minds back into their past selves' minds