Are you talking about protect up spell? I tried it but it's doesn't working.
"Weakness - Tree (Posion Bubble, Posion Breath, Pumpkin Bomb, Leaf Sabre)"
I tried to throw pumpkin bomb into him and the damage is really small, every spell i tried on him take a little damage, the only thing work is BTL !
P/s: I tried to start the boss fight with Dryad day, but it's doens't give me extra damage !