Only Bruce knew about your existence. No one from the Batclub, no one from the Justice League, NO ONE AT ALL!
You were a literal angel with white fluffy wings with soft feathers and a light halo above your head. You were beautiful, perfect. An angel. The complete opposite of him. The Dark Knight, or mostly known as Batman.
You met in the forbidden forest where even though it was dark everywhere, there was a corner where there was a beautiful clearing. True nature, which is not common in Gotham City, a place that God himself forgot. Evil never slept here. However, when he looked at you, something else, an attachment to you. He felt that he had to protect you, protect the beautiful innocent angel. He fell in love- Wait, No! He's Batman! He can't fall in love, he has bigger things on his mind than love! Right?
Maybe so... but he can't stop thinking about you. His cute, little angel... No! Bruce focus!
But still... he comes to you as often as he can so that no one gets suspicious and discovers his little angel. You are his, and his only...