The Western Borderlands
This long sword has a hilt encrusted with fish scales and pearls, while the blade itself is forged from seashells. Despite this exotic material, it is as strong and sharp as a blade of steel, perhaps due to the enchantments placed upon it.
The blade itself has an intelligence residing within it. Prideful and glory-seeking, it will disallow its wielder from attuning with any other magic items once it has been attuned. It can see and hear to a distance of 30’, and communicates with its wielder by sharing its emotions with them.
Once attuned, it functions as a Long Sword +1, and as a bonus action can be commanded to shed (or cease shedding) bright light in a 10’ radius, and dim light 10’ beyond that. Additionally, due to its non traditional materials, it is unaffected by anything that normally affects metal (such as rust monsters.)