Some light reading.
Q: If the effects of Imperial Iron Wall or Artifact Lancea are applying, so that cards cannot be banished, can Allure of Darkness be activated? Also, if Allure of Darkness is activated but Imperial Iron Wall or the effect of Artifact Lancea is chained, how does the effect of Allure of Darkness resolve?
A: If the effects of Imperial Iron Wall or Artifact Lancea are already applying, Allure of Darkness cannot be activated. Also, if Imperial Iron Wall or the effect of Artifact Lancea is chained to the activation of Allure of Darkness, draw 2 cards when resolving its effect. If there is a DARK monster in your hand, reveal 1 of them to your opponent to complete the resolution of Allure of Darkness. If there are no DARK monsters in your hand, send your entire hand to the Graveyard.
Q: If the effect of Necrovalley is applying, can Nadir Servant be activated?
A: Nadir Servant can still be activated. When resolving its effect, send a monster from your Extra Deck to the Graveyard, and add 1 “Dogmatika” monster or 1 Fallen of Albaz, with ATK less than or equal to that sent monster’s ATK, from your Deck to your hand. In a situation where the effect of Necrovalley is applying and there is a “Dogmatika” monster or Fallen of Albaz in your Graveyard but none in your Deck, you can still activate Nadir Servant. In that case, you do not send a monster from your Extra Deck to the Graveyard or add any monster to your hand, but the part of the effect that prevents you from Special Summoning from the Extra Deck for the rest of this turn is still applied.
This was originally posted here, but it seems they’ve greatly expanded on it.
Q: El Shaddoll Winda is on the field, and its effect that prevents each player from Special Summoning more than once per turn is applying. In this situation, can I activate Tri-Brigade Revolt?
A: If the effect of El Shaddoll Winda is applying, Tri-Brigade Revolt cannot be activated. If the effect of El Shaddoll Winda is applying when resolving the effect of Tri-Brigade Revolt, the effect of Tri-Brigade Revolt is not applied, regardless of whether or not you have already Special Summoned that turn. (Not only is the Link Summon not performed, but also the Special Summoning of monsters from the Graveyard or that are banished.)
Q: Null, Dreg of the Abhyss was Special Summoned from the Graveyard by its own effect, and the effect that prevents me from Special Summoning monsters other than Reptile monsters while it is face-up in the Monster Zone is applying. If control of Null, Dreg of the Abhyss changes, which player will not be able to Special Summon monsters other than Reptile monsters?
A: Even in that case, the player who activated the effect is the one who cannot Special Summon monsters other than Reptile monsters. (In other words, even if control is switched, your opponent is not prevented from Special Summoning monsters other than Reptile monsters.)