It might take a few tries because his attacks are random.

Lastly don't forget Envy and you title to maximize the damage. Don't forget to enable both Friendly Formation and Magical Formation. Make sure your last ally does a lot of damage and have your first two allies do quick attacks. Somewhere around 30% of health left, the bird will try to heal it self which should give plenty time to finish him of. Play around with party templates to see which party configuration will deal most damage and don't forget to check on magical effects like the Silver Scale Dragon and Scarlet Dragon. Invest a lot of your habbit into familiars so you have at least 50 familiars summoned which can then all be assigned to Greater Demon. Don't worry on spending Sin and Inspiration to unlock the 5th and last guardian, it is well worth it. Meaning that it should be possible to unlock the last guardian and use those summons in the battle against this boss. If you are on a grind for gluttony, your Guardians Bane should also have increased a lot. Focus through Gluttony on increasing the Magical Attack and Magical Defence. The bird is weak to Earth Damage, so if you are magic oriented be sure to equip some relevant skills. The Corrupted Great Bird is in the boss dungeon of the Evil City, which should unlock after finishing the Holy City. This one is a bit though and requires at least having cleared the first four endings 5 times, preferably also some pride runs and you'll need to have a max destiny of at least 32k when starting the Evil City.

Your chronicle game guide