Adalhard:
Spoiler
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It occurs to you that the Helm of Seven Death's is not some hedge wizard level enchantment, and you realize that it'd be rather difficult to find one. They're relatively old, and rare, creations after all.

You do have some theories of where you might be able to find it, but it'd require finding a Cult of Vecna, and those are relatively hard to find (shockingly, people who follow the secret keeper are good at hiding).