"The Legend of Zelda: Ocarina of Time" has a lengthy side quest that's required if you want to get the strongest available sword. A giant Goron called Biggoron (or "Big Brother" by some of the smaller Gorons) can craft the sword you're looking for, but first you have to present Biggoron with a broken sword. Once you do this, Biggoron will talk to you, and he'll become even more chatty after you run an errand for him.
Instructions
1. Play through the steps for the "Biggoron's Sword" side quest until you deliver the Poacher's Saw to the carpenter in Gerudo Valley. He will give you a broken Goron sword in trade. At this point you can either ride all the way back to Karariko Village before scaling Death Mountain or you can play "Bolero of Fire" on your Ocarina. If you play the song then get out of Death Mountain Cavern before the timer runs out.
2. Walk up to Biggoron and he'll stand up. Biggoron is on the left side at the top of Death Mountain, and he's too big to miss. Speak to BIggoron and he'll tell you that he can fix the broken sword if you get him eyedrops.
3. Collect all of the ingredients for his eye drops. You'll need to go to King Zora in Zora's Domain and the Lakeside Laboratory in Lake Hylia. Return to the top of Death Mountain before time expires, either riding there and climbing up the mountain or by playing "Bolero of Fire" again. Talk to Biggoron and give him the eye drops. He'll offer to fix the broken sword. Talk to him again in a few days to claim Biggoron's Sword. From this point on you can talk to Biggoron whenever you like.
Tags: Death Mountain, broken sword, Biggoron Sword, Bolero Fire, Legend Zelda, Legend Zelda Ocarina