Dark Aura

Yeah, it's a % buff, so it works with matk pots, as far as I know.

Also, checking with a physical classes to see if it's different for them. They did add Dark Aura when INT and Magic Attack were added together to get Magic, so it might be different.

11atk Claw + 15atk Stars + 3 Blessing

 Without Dark Aura

 With Dark Aura

It definitely looks like it's % atk/matk rather than % damage, and it stacks with pots.

 With Dark Aura and 5atk Pot

But... if you have the W.Atk (29), and you multiply it by 1,1, you first need to round it down, then fill it in in the formula to get what he's having on his attack range.... At least:

29*1,1=31,9

1,75*(37*4+25)*(31,9/100)=96,57=97=/=94
1,75*(37*4+25)*(31/100)=93,85=94

Also with the potion, you have to round it down first....