I don't think you can find Mythril Shards in Heartless. Only in Treasure Chests around other worlds.
some are all over the place in chests all over the worlds
Dense Shards are found in Twilight Town, Hollow Bastion, The World That Never Was, and Beasts Castle
Yes, you can get it from Treasure Chests from different worlds, or you can develop a Mythril Stone in the mineral making thing.
Some are random and some are in treasure chests, things like lightning shards, twilight shards, dense shards and those kinds of things are found from heartlesses and nobodies. But things like Orichalcums you find from treasure chests, and some you can get from the heartless that looks like a candy machine
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The following heartless drop the dark shard: Shadow (all worlds) Soldier (all worlds) As far as i know, none of the nobodies drop it
The ingredients for the Mythril Crystal are:1 Dense Crystal (Berserker - The World That Never Was)3 Dense Gems (Samurai - The World That Never Was)1 Twilight Crystal (Sorcerer - The World That Never Was)3 Twilight Gems (Assassin - The World That Never Was)The locations shown are where these Nobodies are commonly found in.
You need to find ingredients for the Mythril Gem recipe. Then find a Serenity Shard, and then you can create the Mythril Crystal.
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There are no Gameshark codes for Kingdom Hearts 2.
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