Galien

Galien is the self-proclaimed 'strongest warrior in Hallownest'.

Strategy
Comparatively, Galien isn't too difficult of a boss. He will launch multiple bouncing orbs throughout the fight. Thankfully, they aren't paticularly fast and dodging them shouldn't be much trouble as long as you pay attention. It doesn't seem like you can destroy them, so simply dash out of the way while getting as many hits in as you can. Be careful when trying to heal, and if you're having trouble, the Quick Focus charm can be quite helpful, despite its high cost.

Dialogue
Hoh, a fellow warrior, out here? I thought I was the only one brave enough and strong enough to survive in this foul, forgotten pit.

I am Galien, the strongest warrior in Hallownest! I came to this monstrous place to test my strength. No doubt you wish to test your might as well, hmm?

Yes, you and I are a rare breed, quite unlike this poor fellow who has fallen before us. The world is not kind to the weak, I fear.

So then... shall we do battle? Let us test our strength in joyful combat!

Upon defeating:
Unbelievable... I am defeated at last! So this is what it feels like to be bested...

Still though, I am strong, am I not? When you see our King, surely you'll tell him of my valour...?

Yes... he sent you here to test me, didn't he? I knew he had not forgotten brave Galien.

I am ready... to join you now. Brothers, you and I. Let us leave this place...

... together...

Upon inspecting his body:
The body of a fallen warrior.