Magician/Merl forest

Exploring the forest
Mage: use lightning.

Toadstool spirit: it attacks using venom; it is weak against lightning.

Talk to everyone for important clues and some magic. Buy everything you can afford. Avoid flying enemies is probably easier than killing them.

Face tree: use two obvious spells to learn more about the level boss.

BOSS: guardian serpents
Give three portions of food to the beggar. The most convenient you can give him are crusts of bread. He will give you three clues about the riddles of the guardian serpents. The third clue is the most important.

You can skip the first door, as the talking tree clued you in.

The second door actually leads to a trap: limit yourself to the first item in the chest.

The second door is the exit from this level.