Crest Location: This can be found atop Mt. Gagazet. Do you remember that promontory where you battled Seymour Flux? It’s the area just past the only Save Sphere on the long, linear mountain trail. As you leave this promontory towards the Gagazet caverns, look behind one of the pillars on the path; behind one, you’ll find the Crest in a chest.
Sigil Location: Go to Macalania Woods. As you go through the main area, you’ll be able to see a man and can speak with him to play a butterfly-hunting minigame; simply hunt down all of the blue butterflies within the time allotted to win. You must play both minigames offered as well to get the Sigil. It’s simple enough, probably the simplest of the Sigils.