Aether Spirit

An Aether Spirit is a human who was killed by (or had) a potent source of Element 115. As opposed to reanimating as a Zombie, the corpse of the human dissipates, and in it's place rises a cloud of pink dust. From there, the spirit is free to do whatever it desires.

Abilities
Aether Spirits, naturally, have various abilities which involve Element 115. They are capable of turning dead bodies into Zombies at will. They can invade a person's mind, and can willingly speak to them. Aether Spirits also have what is known as 'Aether Abilities' which includes but is not limited to Fire, Beams or Balls of pure 'energy', soundwaves, tsunamis and earthquakes.

All Aether Spirits are linked to Power-Ups, more often than not one will arrise as the 'Announcer' in order to escape the painful sensation felt whenever a power-up is obtained nearby. Although only Max Porter and Gruntijackal have ever became Announcers.

Aether Spirits can inhabit inanimate objects by using them as a shell of sorts around their being. Gruntijackal used the bones of a thousand dead survivors to be his shell so he could get around without being exposed.

Aether Spirit power varies depending on the amount of Element 115 was on their person when they died. For instance, the original Aether Spirit is the most powerful as he was electricuted by perhaps the most potent amount of Element 115 as he was experimented on very early into the element's history.

Aether Spirits are incredibly resilient to bullets, shrapnel and just about anything. Upon death, a Spirit will explode and cause a massive amount of the damage to the area around it.

Essentially, Aether Spirits (physically) are just pure Element 115 amplified by the conscionse of the victim. As such, things that destroy Element 115 will also kill Aether Spirits. As such, when Hiru Masaki activated his device, the majority of Spirits died as they wern't high enough in Earth's atmosphere to escape it.