When a pirate uses a sword that has a skill such as Bloodfire, causing the blade to light on fire, the fire on the blade can only be seen by the person using the sword.
There is a glitch that when a person has their blade on fire because of using Bloodfire, and then quickly switches to another sword, the fire will seem to "carry over" to that sword. Unfortunately, it doesn't apply any extra damage than if you were actually using your Bloodfire sword - hence, it's just an affect.
So, nothing special, just a usual glitch. Sorry to crash the party
