—Tanya, in her Mortal Kombat: Deception ending.
The Ultimate Overlord of the Realms is a title given to the supreme ruler of the realms. It is not known whether this includes overlordship over all the realms, or only the six "main" realms (Earthrealm, Netherrealm, Chaosrealm, Outworld, Orderrealm, and Edenia) mentioned in Mortal Kombat: Deception and others. The term is briefly and only mentioned in Tanya's ending for Deception. Tanya is the only known kombatant to be given such a title after defeating Onaga with the One Kamidogu. The "Ultimate" in the title shows that she is the complete ruler of the realms, and not just one realm or a district of a realm, such as Overlord Zeffeero is. It can be inferred that Shao Kahn can also be referred to as this, after conquering all the realms with Blaze's Essence in his ending of Mortal Kombat: Armageddon. However, the term does not comply with the Mortal Kombat plot and is only mentioned in Tanya's ending.