For the ritual you require proving to him giving you the curse mark, that you are worthy, to do this you must battle him and let him judge you, if you pass that stage you then move onto the next. You must gather 3 items. A wolf Bane flower. A blade forged by the great altar first used to create the curse mark, and a container of the blood of only the purest of creatures, a unicorn. Him giving you the mark will tell you how to obtain these items, once done you place them on a pyramid like item in the middle of a room, where you must then enchant them powerfully by saying special words Maledictionem Maledictionem. Once done you will fall asleep, waking up with this mark on your chest. Its now yours to use. However yourself can never have more than the 2nd state of the mark.