This article is from the Final-Fantasy and other Square Soft Games FAQ, by email@example.com (Nick Zitzmann) with numerous contributions by others.
Earth Scroll: After saving Steamwood from almost certain disaster,
return to the mountains. After crossing the river, head left. Race
Rootrick to the top of the cliff to find the scroll.
Earth Guardian: Find the four people the elder asks you to find after
obtaining the earth scroll to proceed through Hell's Valley and fight
Water Scroll: After defeating the group of giant vambees, get the rope
from the church and climb down the well. You can't miss it!
Water Guardian: Once you get the angel key from the church, head back
down into the restaurant dungeon and unlock the big door which is
straight forward from Musashi's starting point. You'll go through a
little dungeon; the crest guardian is at the very end of this dungeon.
Fire Scroll: Once the mayor's wife gives you some salt, go down to the
beach and use the salt on the slug guarding the way in. The Fire Scroll
Fire Guardian: He's at the end of the ice palace.
Wind Scroll: After defeating the fire crest guardian, head to the fire
crest to get the Wind Scroll.
Wind Guardian: She's at the end of the dungeon which opens up after
saving the gondola from the giant ant. Once you finish the little
boulder-dodging mini-game, the guardian will appear in the next chamber.
Sky Scroll: If you haven't already done so, look for the earth crest and
activate it to climb the cliff. Activate the nearby wind crest (see the
Sky Guardian: You'll find it, oh yes you will!