This drama cd is a tokuten/special bonus included in limited edition for Armen Noir PS2 by Otomate. Despite the seriousness of main story, this drama full of humour, and we can see the Hunters and Criminals go along together forgetting that their are actually enemies .
"Crimson Sensei no Shinsatsushitsu” or in english “Dr. Crimson’s Examining Room” told us a story of Crimson’s job as the only doctor in 999 area. Today, he is busy with several patients (and most of them actually don’t have a real sickness), including Zecks, Elle, Knives and Rain.
Note: this article is full of SPOILER for the drama cd, read at your own risk.
