Lots of Mugwort Herbs
After you meet Koris for the first time in the Beetle forest, when he says he will train you, select "Attacks and Defense" and start training. He will give you a Mugwort herb. During the battle, on the first, second, or third turn ignore what Koris tells you to do and select a different command (except item) and he will tell you that you must obey. The fight will end and you will have an extra Mugwort Herb! You can repeat this until you have as many herbs as you like. Unfortunately, the item maximum is 20.


Easily Beat Bird Man
To easily beat the Bird Man, use fire minions. They will make the process a lot easier. Just in case, have plenty of Mugorts ready.