The effect to Summon one Level 4 or lower monster per turn is likely the only "real" effect of the original card, as it was the only one Leon knew about. The other effects were likely the result of Zigfried's hacking.
Solomon Muto also mentioned about the huge cost to maintain the card on the field. Therefore, sending half of the Deck to the Graveyard or the prohibition of Normal Summoning is most likely also a "real" effect.
Also, Solomon Muto (at least in the Japanese version) says that the card had that huge cost, because of the overwhelming effect of destroying any monster the opponent attacked with. So, very likely, the only hacked effects are "cannot be destroyed" and "opponent pays the cost" (the only 2 effects he also makes known are hacked).
Pursuant to Leon von Schroeder's Fairy Tale Deck theme, the "Golden Castle of Stromberg" appears in The Raven, from Grimm's Fairytales.