Who creates the tasks from the user story?

Who actually knows how to "build" a Product Backlog Item ?

by reviewing SCRUM in detail, there is one question that rised:

It is clear that the Product Owner is responsible for the Epics and user stories. But who does derive the tasks from the user stories?

Are you sure that Scrum has anything to say about epics, user stories, and tasks at all?

I echo @Ian's question. The user story concept is not unique to Scrum and is not even mentioned in the Scrum Guide.

But if you do choose to use user stories, @Oliver's question comes to play.  If your Product Owner is creating tasks what does that say about this from the Scrum Guide?

• They are self-organizing. No one (not even the Scrum Master) tells the Development Team how to turn Product Backlog into Increments of potentially releasable functionality;

Hello,

From my past experience, the developers were creating tasks on User Storys.  

But also worked where Tech. leads were creating tasks for the Dev. team, actually this one I don't consider as part of the Scrum framework, as far as the scrum teams are self-organizing.