"Caster" was a term referring to a user of mana (a type of "old magic") in the Fixed Star Era. In the Toward Stars Era era, Caster refers specifically to an antiquated weapon that fires specialized shells.
According to Ark Manaf, "Caster" once referred to individuals (wizards) that cast spells using the naturally occurring energy called mana. However, when mana began to dissipate from any given planet, Casters worked to find way of harnessing the power before it vanished completely.
As a result the spell gun was created and mana was harnessed in specialized shells that could be fired from the spell gun. However, as time progressed, the use of mana and spell guns became a thing of the past. The term eventually was affixed to the weapon and not the user itself.
Casters as weapons
- Main article: Caster shells
Almost a hundred years after the initial creation of spell guns, Casters and their shells became scarce in the Toward Star Era. Casters are considered antiques, their magic old. Prior to the beginning of the series, outlaws Gene Starwind and Ronald MacDougall obtained a gun and staff type caster respectively. Against far advanced magics, such as Tao Magic, casters are able to nullify or block attacks. Against each other, casters cancel the other's power out.