Every connection the archive has filed for this mystery — evidence chapters below, predictions right, theories left, related mysteries above, entities on the outer ring. Anything beyond your ⚓ progress stays veiled until you get there.
On Elbaf’s Sun World, the giants’ children fall into a sleepwalking trance while the monsters they drew in a “what are you afraid of” lesson manifest as real beasts. Who is doing it, how, and to what end?
What we now know (who / how / to what end)
The two opening theories (it is Killingham’s power; the ship is for abducting the children) have both largely paid off on-page — the question has moved from “who/how/why” to a set of tighter unknowns (below).
Who — St. Killingham. His authorship is confirmed and keeps hardening: his nightmare-monsters (“sleeptids”) manifest the children’s greatest fears (Ch. 1172, Ch. 1176); the God of Rain ZaZa is captioned outright as “Killingham’s Sleeptid” (Ch. 1187); he steps into direct combat wielding the founder-weapon Longinus (Ch. 1189). His fruit is the name-carded Dragon-Dragon Fruit, Model: Kirin (“Dream-Manifesting-Man,” Ch. 1143) — though the power is classed on-page as “sleeptids,” never captioned “Devil Fruit,” which leaves Robin’s fruit-hypothesis technically unconfirmed.
How — sleep + drawn fears. He puts the giants’ children to sleep, steers them sleepwalking, and pulls monsters out of their dreams through open “nightmare holes”; the beasts are the children’s own “what are you afraid of” drawings made real (Norse bestiary — Elbaf’s Legendary Monsters). Transformed giants revive from any wound and revert only at fatal damage (Ch. 1176) — except that Chopper’s plain blows cure the demonization outright (“flip back to white,” Ch. 1178; mechanism unexplained — see Choppers Strikes Cure The Holy Knights Demonization).
To what end — race-enslavement, not mere leverage. The purpose is stated on-page Ch. 1186: holding the giants’ children hostage lets a Holy Knight mind-control and enslave the parents “at will” — “simply abduct thy children… I can control thee at will… thou art my slaves!!” — framed as echoing a defeat Elbaf’s race suffered “800 years ago.” The child-abduction is the mechanism of subjugating the warrior nation for the Holy Land, not just bargaining leverage. See Holy Knights Plot To Kidnap Elbafs Giant Children For The Holy Land, Elbafs Race Suffered Defeat 800 Years Ago.
Still open — spun-off sub-mysteries + minor tails
The two substantive open questions now live in their own Threads: