Atop Eldin Mountain, you make your way past lava and monsters to reach the Lizalfos Burrow in search of the elders.

Explore the Lizalfos Burrow

Go north through the door.

Defeat the Lizalfos and open the chest to get 5 rocktatoes. Go north and defeat the next Lizalfos, then go through the north door.

Defeat the two monsters in this room. There will be a cutscene. Afterward, learn the Lizalfos Lv. 2 echo.

Go north to the next room. Defeat the Fire Keese and learn the Fire Keese echo. Then defeat the Lizalfos Lv. 2 and go north to the next room.

There will be a cutscene. Afterward, use monster echoes or swordfighter form to destroy the remaining dark Lizalfos.

If you haven't cleared the Rock-Roast Quarry, do that next. Otherwise, return to Goron City to learn more about the Crater Shortcut.