How to Complete Teach a Man to Run
The objective is to protect Enchan and defeat all foes. The fisherman will not help in the battle. If he dies, you will fail the quest, so be sure to keep healing him.
The enemy is a Rafflesia, and the Rafflesia can also create Malboros. You will have to deal with a lot of status ailments in this battle, so be sure to equip someone with a Ribbon, and bring someone who knows Esuna. You can equip someone with a White Staff and hit Doomed units with it to remove Doom.
The Rafflesia can inflict Poison, Silence, Slow, Blind, Sleep, and Confuse, and the Malboros can inflict Blind, Poison, Silence, Toad, Doom, Confuse, and Immobilize.