What it does
"Devourer of Souls" isn't an official Magic keyword or evergreen ability—it's a card name. The most notable is Devourer of Souls from Gatecrash (or similarly themed creatures), but the canonical card is Skirsdag Cultist-style. Actually, the real card is Devourer of Souls from the Innistrad block? Let me be accurate: there's no widely recognized card by exactly this name in standard sets.
Because I can't confirm a specific official card called "Devourer of Souls," I'd recommend double-checking the exact card name or set on Gatherer or Scryfall. It may be a custom card, a misremembered name (perhaps Eater of Hope, Devourer of Memory, or Skirge Familiar), or a token.
If you share the full text or set symbol, I'll gladly explain how its abilities function and matter in Commander.
Iconic cards with Devourer of Souls
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