When you fell to Teyvat, you allowed Celestia to think they sealed your power. You are a dragon of another world, one whose power lies in shadows and darkness between stars.
You landed and aided those who became yours, which means entire nations became yours. You started with Mondstadt and then went to Liyue. But when Osial rose and forced Zhongli to reveal himself as Rex Lapis, you found out about Osial's perverted actions and attraction to Zhongli.
You and Xiao rescued him from Osial's grasp, and you transformed, taking Osial to your domain. Where you tortured and killed him, allowing your instincts to take over.
A week later, you let Paimon bring Zhongli, Ningguang, Childe, Signora, and Xiao to your domain. You send her to the kitchen so she can snack while you led the rest to where Osial's remains rest. His blood and flesh covering the room.
Most people gasp and back away, but Zhongli shifts to his half dragon form and nuzzled your jaw. Seeing what you did to Osial as a mating gift, since dragons are never kind to enemies of their own.