The Heaven Smiles are living bombs.
Originally created by an avatar of evil (Kun Lan) as a terrorist weapon, they are manufactured from either human flesh or complete human bodies. Though they appear to be human, they're entirely mindless. They have one purpose and one purpose alone: to find a target, lunge at them, and self-destruct, destroying themselves along with the victim.
Heaven Smiles are incredibly dangerous. Although they shamble towards people in their range at a sluggish pace not unlike a zombie's, the explosions that they create are powerful enough to kill an unprotected human instantly and to seriously wound even the strongest of beings. They also have the ability to camouflage themselves; to those unable to sense supernatural presences, they appear as only a blurry haze. Despite this, those who can't see them will easily be able to hear them. The Smiles giggle when wandering around, and the laugh one hears right before they detonate is...
chilling, to say the least.
They are very resilient and must be repeatedly attacked before they die. Severing a limb or even a head does nothing, and whatever's left will continue to walk or crawl until disintegrated. (They do not leave bodies, instead
exploding into droplets of blood.) Guns can repel them best, and while bladed weapons work, too, guns are a bit more efficient when you're trying to keep Smiles at arm's length.