The greatest champions outside of lane to counter 天启者 include 祖安花火, 残月之肃, and 战争女神. These are all good at countering 天启者 with decent win rates over 59%. Even if these 天启者 counter picks are not taken in the same position as you, it's not smart to play her into any of these matchups. They will usually beat 天启者.
Conversely, if the opposite team brings either 巨魔之王 or 死亡颂唱者, you should strongly think about picking her, as she easily crushes these selections with win rates over 52% against both ofthem.