The creator of a system object is a user on whose behalf the object was created and to which account it belongs. Initially (when creating an object), the user-creator gets full access rights to this object and can also give other users access to it. The creator of any user automatically gets full rights to all the elements created by this user.
Building a hierarchy with the help of the creator allows to divide the amount of work between several users, assign different rights to objects, and also reduce the amount of processed information on the screen at the expense of 'unnecessary' data.
There cannot be objects in the system that do not have a creator. The creator is assigned when creating an object and cannot be changed later. Usually (when a user, a unit or a unit group is created) the creator is selected from the list of existing users. However, when a new account is set up, its creator can be created with it simultaneously.
To assign a user the creator of an object, you need the Act as given user access right, as well as a direct hierarchical relationship to it. The users than cannot be assigned creators of an object, are not shown in the list of available users. If an object is created by means of copying or you do not have manage rights to any user, the field of selecting a creator is unavailable and the current user (i.e. you) is assigned the creator. While viewing the properties of an object, the creator is only shown if there is some access to this user.
It is impossible to delete the user that is the creator of some object. You first should delete the object. For basic users it should be done manually. As to the account creator, it is possible to delete it only by deleting its account.