Yami no Matsuei dj - Canary

From Half-Baked scans:
Sequel to Enigma - Seikon. An anxious Tatsumi confronts Tsuzuki about his visit to Kokakurou. Tsuzuki attempts to reconcile things between them, but when guilt and self-loathing threaten his sanity again, Muraki appears with a shocking revelation. In the omake, Za Chienji - Sequel (The Change), Watari's cure may be even worse than the problem.

Pairing: TatsumixTsuzuki, MurakixTsuzuki, Muraki/Tsuzuki/Tatsumi; appearances by Watari, Count, Hisoka.
Spoilers: Kyoto arc - manga volumes 7-8, anime episodes 11-13