What does the improvement "Down Strike Up" give?

It has no description, and google didnt help.

I suppose it would be a new way to hit with the sword but i can't figure out how.

Also if you're already answering the Question, there are 5 ranks, what does improve by rank ?

Solution 1:

It increases the damage of successive down strikes.

I think ranking it is something like this:

Depending on the rank each successive down strike will do 10%+/20%+/30%+/40%+/50%+ of your initial down strike, and capping at your standard attack damage or two times your normal down strike.

If you do 100 with a standard attack your down strikes will do:

• rank one: 50,55,60,65,70,75,80,85,90,95,100...
• rank two: 50,60,70,80,90,100...
• rank three: 50,65,80,95,100...
• rank four: 50,70,90,100...
• rank five: 50,75,100...

and it does keep track of decimals it just doesn't show them, if you have 161 damage on your standard attack at rank 5 it will show 80,120,161, not 80,120,160,161