This is an incredibly powerful 'mythic', or 'ergon' to be more precise, but if you're thinking of undertaking the trials for it beware of what is involved.
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~ Legend Rank in ALL Coalitions.
~ x13099 High-Purity Bayld across three upgrade stages. (100 - 500 - 2500 - 9999)
~ x200 Ghastly Stone / x200 Verdigris Stone / x200 Wailing Stone
~ Various Delve MB drops/crafting materials.
~ Yggrete Crystal (2,500,000 Plasm)
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The main roadblock is the High-Purity Bayld which can cost anywhere between 30k and 40k depending on your server. Therefore you're looking at a pricetag anywhere between 392,000,000 and 523,000,000 gil.