The Nephilin are hybrids of humans and angels. There are three remaining Nephilim in the Phantom Universe, Raven, Traiven and Eve. By default they possess power equivalent to an average Arc, but if they can learn to control their emotions as the Angels do they're power can be equal to a full blooded Angel. Being half human gives them the mental capacity of a human making it harder for them to control their emotions then the Angels.
The Kaiju are a creation of the former demon king Samael. They are a clan of Shapeshifters, similar to a werewolf. They look like normal humans, but if they are exposed to enough lunar energy such as a full moon they are transformed into powerful creatures controlled by the demons from hell. They are immortal in the Phantom sense, meaning they don't age past thirty, yet they can be killed. Over time the Kaiju begun to lose trust in the demons and found a way to break-way from their control. Now they are a neutral clan who lives for themselves. They have no permanent planet, living mainly in space with a fleet of large ships. Their command ship however is the size of a small moon and shaped like a sphere allowing it to emulate a full moon whenever they need it.