[Chaos]

Vydel gains a lot of damage from Greaper, scales tremendously well and can displace and knockdown an entire team with good positioning, as well as deal a shit load of damage to them, at some points it not just Evokers that benefit so heavily from using it, its anyone equipped with a Saturn Badge or has access to Talvyd, and equips a tome as well.

This sounds like a cry to nerf Vydel, not Tarnada. All the katana does is provide an unreliable method to throw out a tornado, and forces a strict build on anyone wishing to make it happen at full capacity, assuming the user builds enough critical and doesn't run into any Liches. An Evoker can do a far more consistent and powerful work, alongside inflicting KD just by starting up the invocation.

Seeing as Vydel is the only reason why Tarnada is still relevant today, the worst of a nerf it would need is either a 1-2 round cooldown on throwing out Vydel, or a lower activation rate.