Tear (boyxboy)

When the legend of a mystical creature turns out to be true. A group of pirates try to collect the tear of a mermaid they captured, not realizing that to every myth there's a dark truth behind it.

Captain Shiloh is a man so ruthless that his ship is usually left alone. Blade, the first mate, was a nobleman with a rich and powerful family but when they get falsely accused he runs away and goes into piracy to collect enough money to save his family.
The two men became friends over time, and yet when the crew accidentally catches a mermaid that friendship is tested to the extreme.