What is understood from referring to this Savior in various religions is that each of them believe in a single savior that will take the control of the world and will bring it into justice and tranquility. They do not believe in many different saviors and do not say that there is a savior among the Jews, one among the Christians, one in Islam, and so on and so forth.
As a result, there is two facts:
Firstly, to believe in a savior should be a true belief since we see that all of the religions talk about it and it is impossible to say all of them are mistaken and say something wrong.
Secondly, when again we see that all of them talk about a single savior there should be just a single one not many saviors.