Tips for Kingdom Hearts II - Day two

Find... Mythril crystal
Find it Enemies don't drop these, which can be a pain. You can only find them randomly in treasure chests, or by synthesizing them from mythril gems. Use them to make the Ultima Weapon

Find... Orichalcum
Find it This extremely rare item is dropped by the fabled Bulky Vendor. See the FAQ on the right for more details and where to find him. A more powerful Orichalcum 'plus' variant also exists.

Find... Power crystal
Find it These are easy to get hold of, providing you know where you're looking. Go to the Beast's Castle and defeat a Morning Star; most of the time they'll drop one. But be persistent.

Find... Serenity crystal
Find it The tower in Twilight Town and the World That Never Was both play host to these crystals. Find them by defeating either Assassin, Berserker Samurai or Sorceror Nobodies.