To unlock a panel, I need to defeat two of the Hewdraw heads at once on any intensity. I have tried a few times already, and it seems that wearing two heads down and using an ultimate attack doesn't defeat them. Has anyone done this yet, or do you have an idea, weapon type I should use or strategy to do this?
On 0.0 intensity, use any club or staff weapon's special (power) attack by tapping the one of the two blue orbs at the bottom touchscreen (they regenerate after use). This attack will damage all three heads.
Three or so should be enough. You can hit each head with a charged attack and then use two special attacks.