The Unnamed Sword

"Look at the crystal ball son," Merlin commanded.
Gawaine looked. Inside the shimmering ball, he glimpsed a pallid young girl on a hospital bed.
"Elli's dying, Gawaine. In weeks, she'll be dead. Only two ways she can be saved. One of them lies in Camelot's wilderness. You must quest for the Silver Chalice."
"And, if I can't?" protested Gawaine.
"There is another way but it's too difficult even for me to mention."
"There seems to be more," Merlin continued. "I see a speck where it should be clear. A dark speck. Wait please."
A moment later, four huge creatures that seemed a cross between a mass of writhing serpents and gigantic squash on legs rampaged the length of a village, leaving nothing behind but raw earth.
Merlin looked hard at Gawaine. "There's a second labor for you, it seems. What now see are hydras, nightmare creatures from another place and another time. You must destroy these hydras before they and their kind consume your planet. Yet, unless you learn the name of your blade, it cannot be done. And, unless you save Elli, you have no hope of learning your sword's name."