The greatest champs not in lane to counter 德玛西亚皇子 include 虚空之女, 寒冰射手, and 皮城女警. These picks are all good at countering 德玛西亚皇子 with decent win rates over 60%. Even if these 德玛西亚皇子 counter picks are not picked opposite your position, it's not smart to take him into one of these matchups. They will likely win against 德玛西亚皇子.
Yet, if the enemy team choses either 复仇之矛 or 影哨, 德玛西亚皇子 mains should seriously think about taking him, as he easily beats these champions with win rates over 52% against both ofthem.