Dark Lance Idea

Lance sat in a large gold beautiful canary cage. His soft purple eyes gazed out the bars. He shifted closer to the edge and held onto the cold steel.
  Loud foot steps fell, revealing a tall figure with purple skin and long silver hair.
Lance tilted his head and he fluttered his lashes, “Prince?”
Lotor flashed a small smirk, “Yes, my pretty song bird?”
“I feel.. Lonely,” the human male spoke softly, “I miss… I’m missing something.. Or someone.. Am I missing you..?”
Lotor walked close, looming over him, “Yes, you were missing me. You want company..”
Lance looked to the floor, tears pooling down, “Are you sure it is you that I am missing..? My eyes.. They have so much.. Tears.”
“Yes, yes it is. And it is I that shall wipe them away..” Lotor used two fingers to brush off the tears from Lance’s face. The galran prince lifted the human’s face gently, “You are appreciated, my dear. No need to cry.”
Lance sniffled, “I am..?”
  “Yes. Yes you are.”
Basically, Lance is put under a strong hypnosis (which makes his eyes purple) and forgets about voltron and the other paladins.
(As you know- hypnosis cannot work unless the one being hypnotized agrees to do so…)