The flashback sequence in episode 22, where Chouji Suitengu is finally reunited with his long lost sister Yui... only to find out that she's been forced to work as a prostitute, has become an insane and broken wreck, and doesn't even recognize him anymore, ending in him killing her out of mercy. This scene gains the distinction of being the one and only time this troper felt sorry for that bastard Suitengu, and actually rooted for him when after the flashback he brutally slaughters the Prime Minister of Japan, who was responsible for the whole thing.
Shinzen Tennouzou was a terrible bitch. Kagura's absolutely heartbroken reaction to Suitengu killing her, as well as Shinzen realizing in her last moments that her hate of Kagura and the whole world was based on a lieandShinzen's backstory as a shy young actress who lost everything still made me cry.
A Crowning Moment of Heartwarming that doubles as a minor Tear Jerker occurs when Suitengu handsomely rewards his four dedicated servants and tells them to leave before he enacts his final plan. Tsujidou and Makabe quietly refuse his request and tell him that they owe him their lives and that they're staying by his side until the end, followed by a painful scene in which they say goodbye to their friend Niihari, knowing that they'll never see each other again.
"We had one hell of a time, Tsujido. Take care of the rest!"
Suitengu's entire backstory. It's completely open to interpretation on whether or not he's a sympathetic villain, but there's no doubt that he's the male version of a Broken Bird. To clarify, his parents fell into debt with criminal elements and hanged themselves, leaving the adolescent Suitengu and his sister to the mercy of the mobsters. Suitengu was sold to an army as a mercenary slave and forced to kill and experience horrors for years, with the only light at the end of the tunnel being the thought of being released from service and finding his little sister again. Then on his last mission, he's blown apart while attacking a biological weapon research facility. Scientists recover his infected body and turn him into a Frankensteinian abomination. After he escapes, he tracks down his little sister (see the first entry for that). After all of that, it's not surprising that he turned into a cold hearted killer.