Additional Obligations. In addition to the obligations of Licensee otherwise set forth in this Agreement, during the Term, and thereafter where specified, Licensee agrees that:

a. Licensee will not attack or challenge the title of Id Software to the Subject Game or the Trademarks or any copyright, patent or trademark or other intellectual property right related thereto and Licensee will not attack or challenge the validity of the license granted hereunder during the Term or thereafter; and

b. Licensee will promptly inform Id Software of any unauthorized use of the Authorized Copy, the Subject Game or the Trademarks, or any portions thereof, and will reasonably assist Id Software in the enforcement of all rights Id Software may have against such unauthorized users.