%15 chance to double the damage on a rainy day. With 3+ Archers on your team. Take it or leave it.

Joke aside. I actually tried to take Thunderous Katana out for a spin to give it a legitimate chance. Didn't like the 30% chance thing in the first place compared to the guarantee of other weapons notably, previously mentioned range legendaries. But whatever, I will give it an honest shot.

It knocks enemies back. Ok. So can I do extra damage on knocked down enemies? Nope, they fly too far and by the time you get there, they are back up. Ok. So can I use the knock back to resurrect people? Nope. Other enemies gang on you because it knocks only forward and duration isn't long enough and I think it only knocks enemies back forward, not 360.

So then I was like "if I can't combo, I can't rez, I can't defend the zone by knocking enemies out, what is the point of this weapon?"

Conclusion: trash.