Coeurls in Final Fantasy Tactics Advance are powerful blue beasts that are related to Red Panthers. They have a large amount of HP and are very dangerous to approach because of their Blaster skill and high Attack power. Luckily, there is usually never any more than one Coeurl at a time.
It is a good idea for your units to use the Judge and easternmost cactus to cover their backs when heading for the Coeurl.
Complete Mission #003: The Cheetahs
Mission #004: Desert Peril
The Coeurl here starts off on a mesa and should take at least three turns to reach the party. Try to eliminate the closer enemies before the blue panther catches up with you.
The four escaped monsters here should be no match for your party, unless the Ahrimans begins to KO most of your units with Roulette and the Coeurl petrifies the rest with Blaster.
Complete Mission #012: Pale Company
Mission #052: Friend Trouble
There are three Red Panthers and a Coeurl here. Try not to let them surround your mages.
Complete Mission #016: The Big Find
Mission #065: Exploration
To unlock Jagd Ahli, you will need to defeat the monsters guarding the gate. The Coeurl starts off on the left side of the screen.
Complete Mission #021: Hidden Vein
Mission #022: To Ambervale
The Coeurl here is backed up a a group of other difficult monsters, including a Big Malboro, Thundrake, and Lilith.
Complete Mission #191: Lucky Charm
Mission #067: Missing Meow
The runaway level 35 Coeurl here does everything but meow. Disabling it or putting it to sleep helps a lot.