Final answer:
When Sera puts up the hood of the Black Cloak, she sees a mysterious and formless figure that seems to skulk behind the front design.
Step-by-step explanation:
When Sera puts up the hood of the Black Cloak, she sees a dark and obscure figure that appears to be lurking behind the front design of the cloak. This figure is formless and seems to provoke curiosity. Sera also mentions seeing a white flash or pin-point of quick light, similar to the gleam from sunlight reflecting on something white.