User blog comment:Dragon´s Blade/World Coexistence Alliance/@comment-24965182-20140905172949/@comment-24965182-20140905211300

John: Yeah, in the past Guardian Beast also known as Summom Creatures were called for war purposes,  and now is still that way,  but with less conflict.

Sugar: Also a Summonite can only summon a Guardian Beast.

(The gem turns pink)

See? Some beast are only called when needed and others preffer to stay with their masters.