EPM Admin users - do they need to be a named user?

I would like some input or guidance on where the system automation jobs should be assigned (Id, etc.)  We did not want to use a named user in the event the person changes jobs or leaves the company.  Most system that I have worked with in the past had a “system” id that these could be tied to. Is there a system ID for EPM or does it have to be an assigned user? Are their admin account automatically created?