librmgr has the functions rmgr_task_new and rmgr_task_new_with_prio. pager can use these to let RMGR create new tasks on its behalf. Thus, the newly created task's chief will be RMGR, as it is the chief of all the tasks started by RMGR from menu.lst. Not surprisingly, sigma0's chief is RMGR (i.e. the root task).
Hope this helps, Uwe