Violinist of Hameln/Heartwarming

Too many to count, though the ones that stand out the most are probably when (as mentioned above) Flute is stabbed in the chest by Hamel but still smiles, trusts him, gets up and takes his hand and when Hamel and Sizer are reunited with their mother.
In the Violinist of Hameln manga, fist volume's last chapter, we're treated to the sight of Jerkass Anti-Hero Hamel carrying a battered Flute on his back into the sunset, even though he had been the one to puppet her into a hopeless fight against an enemy he knew she couldn't defeat (throughly played for laughs). (Predictably enough, by the third volume, even a kid they just met could tell they were totally not in love, and mocks them accordingly.)
In the third volume, Hamel's Nice Hat falls off during a Freak-Out caused by the triggering of his demon blood, and accidentally reveals his lone little horn. Raiel tries to calm him down by attacking him with snow dragons, which doesn't work too well; however, upon learning of Hamel's parentage, Flute immediately jumps into the battlefield, hugging him from behind and crying while saying she finally understood his pain. Hamel imediately calms down, puts his hat back on his head, and starts playing his violin for the previously terrified villagers around him. The heroes go right back to their wacky hijinks a page later, but after the tension of the previous chapters, it's almost a relief to see Flute bashing Hamel with her Cross of Divine Retribution again.
Subverted and played straight twice over in a particularly memorable scene, which had a volumes-long setup of flashbacks featuring how Hamel became the jerk he is, punctuated by the Monster Clown's long and elaborate plan to make him permanently Freak-Out, and which climaxes in an "I Know You're in There Somewhere" Fight that doesn't work at all. When the Monster Clown's victory seems certain, Flute walks in the scene and Hamel starts ripping his own demon horns and wings out, begging her not to come closer. Obviously, she does, right when some guards decide to be HeroicBystanders and shoot his back. He freaks out again, stabbing her right through, but she still holds his hand, using her healing magic to turn him back into his usual form. By this time, Monster Clown is raving about how all of that couldn't possibly be happening (justifiable as he had taken the Power of Friendship in account). However, the heroes turn after the battle to find Hamel clutching Flute's bloodied body against him, clearly about to cry... when Queen Horn teleports in to heal her, having apparently let it all happen so the two could overcome their demons.
Raiel restoring Sizer's soul to her body. Took care of that whole What Is This Thing You Call Love? problem of hers, too.