Ez, keep fusion summoning Ojama Knight using your Ojama Knight (equipped with masked of Accursed) and another Ojama monster. Your opponent only has 2 Mask cards, and you have 3 Poly which is enough to deal with. Last turn, use Ojama Country to special summon another Ojama Knight from GY or fusion summon if you haven't use all your Polys.
Do not summon 2 monsters except during your last turn, always fusion summon Ojama Knight to lock 2 monster zones of your opp. If you can't manage to lock 2 zones as he already has 2 monsters on his field, keep attacking so he only has 1 which keep him from tribute summon Des Gardius, as he will use Jeroid to reduce your atk. Good luck bro.
I don't really remember but i think you should summon knight in defense mode and keep it like that till last turn. If i recall correctly, he won't equip mask of the accursed on a 0 attack monster. In last turn you summon 2nd ojama knight in attack, play ojama country switch your 2nd knight to attack and then, you summon vassal, and for nightmare wheel use anti magic arrows.