A horizontal line appears when setting "Fafnir Fulmination" as your accent while editing a portrait.
Line remains no matter what lighting or frame you choose as long as "Fafnir Fulmination" is the accent. The line also remains even when finished editing.
Frequency: Constant
World name: Coeurl
Character name: Fwee Fwee
Steps:
1. Open "Portraits" and edit one.
2. Under "Design" tab, change accent to "Fafnir Fulmination."
3. Behold.