The Dark Kind came to the world as conquerors. They failed. Now they are odd neighbors.
HeartKind bands are a way for Dark Kind (or any Deamonic/Monsterous kind) to show that people have nothing to fear from them.
As part of The Pact that ended the Six Stars Demon Wars, various places were given over to the Dark Kind. This is their neighborhood in the city.
In this culture it is not wise to talk too much good things about anything - especially children,lest some evil spirit steals it. So it is customary to say it is ugly and weak and will surely not survive. Also:
"The man who boasts of his young woman is a fool,
The man who boasts of his wares will get rich."