Fresh from Konami’s own website! http://www.yugioh-card.com/japan/topics/?20140403
Extrapolating from the article, the effect appears to be (as in not confirmed yet because the effect is blocked again):
Light Fairy / Effect
When this card is Summoned: You can Special Summon up to 2 “Ra’s Disciple” from your hand or Deck. You cannot Special Summon monsters, except “Ra’s Disciple”, and you cannot Tribute Summon monsters, except Divine-Beast-Type monsters.
The unconfirmed stuff include how many times you can use the effect per turn (as in is there a name-based once per turn?), and what other effects (if any) it will have. The negative effects are confirmed, possibly worded differently.