Imouto wa Scyllakko

Shamuran is a Scylla (an eight legged monster girl), who has been under the care of her adoptive family since birth. Despise being a monster, her personality caused her to be incredibly popular and she gets constant marriage proposals.... However she always rejects them without thinking twice. Her older brother can't figure out what's wrong with her lack of interest in men, but (fortunately) he is going to find out soon enough.

Note: Published in Comic Unreal Vol. 37.