The emblem for the phantoms resembles an upside down star as well as a face that looks mad from fear and anger.
Phantoms are the monsters of Kingdom Hearts Ultima, they are a kind of Unverse/Heartless hybrid. They were once people with achluophobia who lost there hearts and bodies. As souls instead of seizing their body to become a Nobody, they are lost in the darkness, there fear making and turning them into Phantoms.
They fight along side Heartless and Nodoby as they are drawn together just as heart, body and soul. However whatever creation of these three types of monsters combined is unknown but certainly not human.
Trivia[]
The name and idea were inspired from ghosts, in which some people fear the darkness for what or who it may hide, even in safe environments like your own bedroom. Some ghosts even manifest in dark forms even in illuminated enivornments.