Hey,
currently i work in ZBrush with a lot of Video-Tutorials. Now i start with the Character Creation and in the most of all Tutorials i should use ZSpheres, and thats my question. Do i have to use ZSpheres for Character Creation, and in case of YES, why? Is there no other method to create an character?
I like Zspheres, so i have no problem by using it. But i want to know all possibilities. 
Thank you!
Zspheres are simply an option Zbrush provides you to block out quick forms. Since the tutorials you are watching are probably Zbrush-centric, it makes sense they would use Zbrush tools. Base meshes created using traditional methods in other applications and imported in are also perfectly viable.
It’s just a matter of what you are comfortable with.
You don`t have to, you can just create basemesh from something else if you wanted