This is just a cheap digital rip. If you were to scan a real copy you could get much higher resotluion. The back cover might be original artwork, but I know the rest aren't. But I'm not aware of any Valkyrie artbooks out there.

This is amazing! What an incredible thing to see. Though for your comment about a Valkyrie artbook, there actually is on, though it's not scanned anywhere that I know of. Search for "Legend" Valkyrie World Color Analytics Art Book / Valkyrie No Densetsu or ワルキューレワールド カラー設定イラスト画集「LEGEND」 if you want to pick it up yourself some time.

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