Why does FirZen have an Ice-shield???

[Scorpion]

And why question why the shield is made of ice?

Senseless question yes

My opinion:
Firzen can use fire and ice -> if he uses a fire shield he wouldn't defend other balls because they would fly through the fire. And it has to be animated, because fire moves all the time instead of ice. So M and S had to change the defending frames.