Because the only other weapon I've seen that has this effect is a bomb, I believe the 5 star variation of Winmillion should have the following effect.
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Vortex Arc
Each slash sends out a small vortex which pulls in enemies towards the user. 3 hit combo which ends in a 4th hit that damages and knocks back all enemies directly in front of the user.
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Naturally with an effect like this the damage would probably have to be lowered. But it would be handy for dealing with those pesky Strikers in Lockdown. Or Magicats that refuse to sit still.
Eye of the Storm
Like winmillion but is grey, white and blue. The handle has a giant rotor. it strikes 3 hit combo and 6 energy disks, two for each strike. The charge is a blue disk that strikes up to 6 times. The 6th strike is a explosion that scatters enermies with huge knockback, representng an hurricane. The 5 energy disk strikes does no knockback just normal, like how the eye of the storm is clear and sunny.
Picture comming soon: