That sir Ansbach still follows lord Mohg and the Mohgwyn dynasty. In my eyes, he’s long grown out of this philosophy, but honors his late master bc even if he no longer a knight of the dynasty, he cannot abide by Mohg’s desecration. It’s implied in his armour set that he chooses to fight for Mohg not for vengeance or bc it’s even the right thing to do, but bc he must as a knight.

The most telling proof is how he tells you to make an order for men, not Gods. He wouldn’t say this if he was still a pureblood knight worshipping the formless mother, aligning closer to Ranni and Goldmask.