The Lord wasn't confined or imprisoned when he was banished by Mykel, and he was unharmed or anything. He was so sure that Mykel would kill him or erase his existence knowing Mykel's power was beyond his understanding.
Although he was unharmed, he was trapped in a place, small enough that he couldn't walk around. He didn't know why he was sent there in the first place and why he was abandoned and forgotten.
He didn't know how long it had been since the time felt like moving very slowly and it felt like he had been there for hundreds of years. He didn't know what to do since he lost his power, so he decided to use his time to think.
"I wonder why is he keeping you alive," Mykel's voice could be heard from behind The Lord.