Darker Than Black/Heartwarming

"Huang:"That isn't true...is it, Hei? Contractors don't think about suicide, do they? Hey, Shioko...Don't betray me...""
 * When November goes to fight Maki, we get a quadruple one. First, he gives July a note and tells him to go to that location if anything happens. Considering most people treat dolls as human-shaped surveillance equipment, the fact that he cared enough to ensure his safety really says something. Second, it turns out the note was to send July to Misaki--she's the only one November trusts, even though they barely even know each other. Third, when she asks July if he knows where November is, he just replies "Of course. I always keep track of my friends." For the normally emotionless dolls, that's really something. And finally, November goes against his rational nature and fights Maki a second time in order to avenge April.
 * In the episode 25 of Darker Than Black, we have the part where, and the bad guys are scrambling to try to deal with this. ... at which point Hei comes to the rescue. But the real heartwarming bit is when he's about to zap the guy to a much-deserved death and
 * Also, "Kirsi..." "No. Yin."
 * At the end of episode 18, when the supposedly emotionless doll Kenji saved earlier smiles at him.
 * And lest we forget grizzly hard-ass Huang's character development arc. Shioko, a woman who is targeted for assassination by the Syndicate, who orders Huang and Hei to do it. In the end  Hei tries to help them escape, but when  she realizes they can't escape and

"Hei: Only Yin's voice snaps me right back into my senses."
 * Shikkoku no Hana manga has some too. After :


 * When Havoc laughs in episode 6 of Season 1.
 * The epic hugging action between Yin and Hei throughout the OVA. Probably the most genuine acts of affection either of them have in the three series.