Cerberus is a boss fight that takes place in the astral plane. This third giant dog needs to be dealt with in File 3, but before that you will have to make do with the pack of dogs who like to hang out with him.
Astral Chain: How to beat Cerberus
The first phase of the Battle of Cerberus doesn't require you to fight it at all. Instead, you must face off against a pack of chimera dogs who love to follow him. Fortunately, they are quite easy to manage, so choose them one by one. Make sure you use a finishing move to heal any damage you've taken, as you'll want optimal health for the next game.
Once the platoon is dealt with, Cerberus will join the fray. Cerberus uses a combination of area-of-effect slam attacks and projectile attacks to deal damage. This fight is all about dodging. Your tactics are limited as your Legion of Swords will only be unlocked at this point. You have a secret weapon, however. While circling around Cerberus, you can take advantage of Sword Legion's Slash attack to deal multiple hits and do plenty of damage. This should be your priority.
When Cerberus turns towards you, it will normally perform a quick attack. Rolling around to avoid this unlocks a powerful melee attack for you. Make sure you're using your Baton Mode so you can quickly land hits and follow up with a sync attack when you can. The braver you are in this fight, the higher the payout, with well-timed dodges, slash-type attacks, and combos letting you deal almost constant damage to Cerberus.
Once his health is low, he will jump through some platforms and start dropping red energy balls at you. Follow it as quickly as you can on the platforms, then repeat whatever tactic you've used before.
Every once in a while Cerberus jumps into the air and lands on you. Don't try to follow him, spam your dodge to prevent him from falling on you, because if he did, he would cause massive damage. This fight feels a bit like a skill test to make sure you learn how to time dodges and take advantage of the openings they offer, so make sure you're comfortable with the mechanic, and this fight should go well.
