He is as sloppy as a Tsugaru slob.

He is recovering from an illness, and has not fully recovered yet.

Something is moving in the darkness.

He became part of the dark side, and ended up fighting against his former comrades.

Darkness covered his heart.

He was searching for something in the dark.

He bought illegal goods on the black market.

Amemiya-san is my best friend.

He was searching for something in the darkness.

He overcame the darkness of his own heart.