[@Crusader Lord] It truly depends on the caliber of Sorcerer that summons them. Here are two famous sorcerers of note that I can cite as example. Ashur Kai, the White Seer, is served by the tutelary Tokugra, which takes the form of a raven made of shadow that speaks only in rhyme. Azekh the Exile is master of Aaetpio, which has no static form but presents itself as a shifting mass of eyes and wheels of light.