A Dragon Caller is a being with the ability to summon dragon spirits at will into a corporeal form. The dragons summoned are under control of the Dragon Caller who summoned them.
Although a Dragon Caller can summon dragons, they cannot control other dragons that were not directly summoned by them.
Tanya is the only known kombatant to have become one in her Mortal Kombat: Armageddon ending (however, this is a non-canon ending which is separate from the Mortal Kombat plot). In her ending, she creates an army of dragons at her command with a mere thought and conquered the realms one by one.
It is unknown whether or not the dragons summoned by the Dragon Caller will obey Onaga the Dragon King instead, though this is somewhat unlikely.
