Blue is a fan playable character based on the Equinox_Twilight's creations but recreated by topcat13. He is a semi-clone of Blade. However, his attacks are slightly more powerful. He is an unlockable character who could be available by clearing Adventure Mode with Blade on normal or higher. He has light-medium weight.
In Super Smash Flash 2
Blue was previously confirmed to appear again in Super Smash Flash 2, as an unlockable character with a different design and new attacks. But was announced on May 18, 2012 that he would be removed from the roster along with Blade.
Blue's sword seems to be a flamberg type rapier. Note the hand shield under his right hand. This "Flamberg" somewhat emits fire, much like Blade's own katana, which emits electricity.