I taught about what could be the 5* Spur so here is what i came up with.....
The Damage is just about a pinch higher than the DVS and it will still shoot discs upon slashing, As for the design I thought it could be the color red now or blue with some glowing effect on the sword.
The red design is call Nitroblade
The blue is called Cyclone
http://lmgtfy.com/?q=5*+spur+line+spiral+knights&l=1