Enceladus is your first real battle challenge in Astral Chain. You have the face of this giant beast after training yourself in another dimension. Because it happens early in the game, you can still figure out the combat system, which means you could fight this battle.
Astral Chain - How to beat Enceladus
Your best weapon against Enceladus is distance and your astral chain itself. Enceladus often rushes, but before him a luminous path indicates the direction in which he is going to move. The trick is to have your player character on one side and your Legion on the other. Due to this trick, Enceladus gets tangled in your chain and you can then knock him down.
It sends him to the ground, stunned. You have time to do a lot of damage with your Legion and your weapon. Your weapon doesn't do too much damage to him, so be sure to use your baton to give him a few hits, and let your Legion do the work.
Every now and then, Enceladus throws a strange circle of energy around you. You can't access it, but your Legion can. Look for the light blue energy nodes around the circle, bring your Legion towards them to break them, freeing you.
You want to be careful and time your movement carefully. Enceladus performs dangerous area-of-effect attacks that do a lot of damage. However, they are easy to avoid and provide you with openings to damage it. When you see him slowing down and doing one of these attacks, try to roll behind him to avoid the damage. Then hit him with your Legion and weapon.
Enceladus is a great introduction to the feeling of hitting a boss with your Legion. It can put pressure on you, but it's also easy to injure you if you sit at a distance that allows your Legion to do damage. You can then support your legion with the sword. Your main windows to do a lot of damage are after breaking his dash.
Also, be careful that Enceladus doesn't hurt your Legion too much. If he does, your Legion will return to the Legatus and you will be given a delay before you can get it back. When your Legion is gone, it dramatically reduces the damage you can deal and extends the duration of the boss fight. This delay increases the chances of your death.
If you're feeling confident, you can approach Enceladus, dodge his telegraphed attacks, and hit him right after a perfect dodge.