Something like this?
CREATE TABLE #EMP (EmpID CHAR(1),
                   MgrID CHAR(1));
GO

INSERT INTO #EMP
VALUES
('A',NULL),    
('B','A'),    
('C','B'),    
('D','C'),    
('E',NULL),    
('F','E'),    
('G','F'),    
('H','G');

GO

SELECT *
FROM #EMP;
GO

WITH Hierachy AS(
  SELECT E.EmpID,
        E.EmpID AS MgrID,
        E.EmpID AS MstID,
        1 AS HLevel
  FROM #EMP E
  WHERE E.MgrID IS NULL

  UNION ALL

  SELECT E.EmpID,
        H.EmpID AS MgrID,
        H.MstID,
        H.Hlevel + 1 AS HLevel
  FROM #EMP E
   JOIN Hierachy H ON E.MgrID = H.EmpID
)
SELECT H.EmpID,
       --H.MgrID,
       H.MstID
FROM Hierachy H
ORDER BY H.EmpID;
GO

DROP TABLE #EMP
GO