Sybil defense via sequential liveness proofs: each identity must periodically solve a verifiable delay function bound to its key, an oasis of trust only real presence refills. VDF outputs are unpredictable yet cheap to verify, so heartbeat checks cost the network almost nothing. Attackers cannot shortcut the work: VDFs are inherently sequential, so every fake burns real wall-clock time on real hardware, the reef on which fake fleets run aground. Like an onyx seal, each proof is unforgeable and bound to one key. Attack cost scales with fake count; honest agents pay one proof each.