Astral Chain has five total Legion for you to bind with and save after they go rogue early in the game. To this point, we’ve already saved the Sword, Arrow, Arm, and Beast Legions, leaving only one more to go. That final one is known as Axe Nemesis when you face it, which you need to take down to get the final Legion in Astral Chain.
Axe Nemesis starts with a giant bubble shield surrounding it that protects it from being damaged. What you have to do here is summon your Arm Legion and use it to break the shield.
Once the shield is broken, give Axe Nemesis everything you’ve got. Just attack, attack, and attack, but be careful of its most powerful attack where it starts spinning and basically is invincible. The best bet here is to back away and just wait for the attack to end.
When the bubble shield is down, you are able to bind Axe Nemesis with your Astral Chain as well, though it will break out pretty quickly. Eventually it will bring back up its shield again, so just use Arm Legion to take it down yet again.
Keep attacking Axe Nemesis here and soon you will be prompted to press A to Bind when you get its health bar all the way down. With Axe Legion in your arsenal, you now have all Legions at your disposal in Astral Chain.