I found the technique. You have to get the little green enemies out and lure them towards a dryad. You take advantage of the confusion to attack the dryad from behind and press the R key to kiss her. If the technique works, the dryad becomes your ally. Also, if you send her to the ground and press R, you can get a ring to cast the spell from a distance. But it's rotten, it only does 1 damage. My main problem is when climbing the tree, I get wiped out by the enemies to kill on the way, the area is small and you can't get out during the fight. I suppose that the rest of the route leads to the main objective. I think there is another access at the bottom of the waterfall, but it's full of enemies (carnivorous flowers).
