Merlin and The Great Dragon in “The Darkest Hour (Part Two)”

Arthur intends to sacrifice himself to heal the veil. It is my destiny is to protect him, you taught me that.

Merlin, you must not do this.

I have no choice. I must take his place.

From the moment I met you, I saw something that was invisible. Now it is there for all to see.

A lot of what you see, old friend... is what you taught me.

It will be an empty world without you, young warlock.