’s first ability is a continuous effect that can affect many cards. It limits players to the use of "draw" effects only. Alternative methods of gathering cards from your deck and placing them into your hand won’t function while Rai-Oh’s effect is active. This means cards like Reinforcement of the Army and Charge of the Light Brigade can’t be activated, and the effects of monsters like Sangan and the Gadgets are equally damaged.

The trigger effects of monsters, which would normally be constrained only by their own timing requirements, may not even be allowed to activate at all. Mandatory trigger effects that are forced to activate, like Sangan’s, will still activate and start a chain while Thunder King Rai-Oh is face up on the field, but their effects will be negated at resolution. Monsters that have optional trigger effects, like those of the Gadgets, cannot be activated at all.

Effects that "pick up" cards work a bit differently. If the effect is mandatory, it will activate even if Thunder King Rai-Oh is face up on the field, but its resolution ends badly. Any card the "pick up" effect would have added to a player’s hand is sent to the graveyard instead.

Due to the effect of Thunder King Rai-Oh, Player B cannot add either card to her hand. One of the cards will be placed at the bottom of her deck, per the effect of Crystal Seer, but the card that would normally be added to her hand is placed into the graveyard instead. If Player B tries to add Destiny Hero - Dasher to her hand, it will be placed into the graveyard instead.

Cards that may or may not add a card from a player’s deck to that player’s hand can also still work while Thunder King Rai-Oh is on the field. These cards usually have a method that can result in a card being added to a player’s hand, or doing something else entirely. Card-specific rulings mention the trap card Conscription, which can potentially special summon a monster from your opponent’s deck. It can still be activated while Rai-Oh is on the field, and if you reveal a monster that can be normal summoned, you will get to special summon it. If your opponent reveals a card that would normally be added to his or her hand, it will be placed into the graveyard instead.

Effects that add a card from a location other than your deck to your hand aren’t affected by Thunder King Rai-Oh, even if they start the process by taking the desired card from your deck. Gold Sarcophagus and Different Dimension Capsule are two such cards. Each allows you to remove a specific card from your deck, but the card is not immediately added to your hand. The card is first removed from play, and is added to your hand at a later time.

’s second effect is useful against monsters like Dark Armed Dragon and Cyber Dragon, "contact Fusions" of Fusion monsters like Elemental Hero Storm Neos, and Synchro summons. In each case, when your opponent performs the special summon you can send your Rai-Oh to the graveyard to negate the special summon. Any effect the monster has that activates when it is summoned will not activate, so negating the special summon of Gladiator Beast Gyzarus with Rai-Oh’s effect means you won’t lose any other cards.

Players don’t get a refund if the negated special summon involved tributing monsters or sending them to some other location. If your opponent performs a Synchro summon using Krebons and Destiny Hero - Malicious and you negate the Synchro summon with Rai-Oh’s effect, your opponent doesn’t get his or her Krebons or Malicious back. If your opponent returns Gladiator Beast Bestiari and another Gladiator Beast to that player’s deck to special summon Gladiator Beast Gyzarus and you negate the special summon with Rai-Oh’s effect, your opponent doesn’t get his or her Gladiator Beasts back.

Special summoning monsters like Green Baboon, Defender of the Forest, Gorz the Emissary of Darkness, or Dragon Ice starts a chain because their effects are trigger effects. They can be special summoned when a specific event occurs, unlike Dark Armed Dragon which you can special summon in your main phase 1 or 2 if you meet its requirements. Dark Armed Dragon isn’t waiting for a specific event to occur and trigger its effect.

When a monster is special summoned by a card effect that uses the chain, the monster’s summon is considered to be successful when the effect resolves. This means you can’t wait until after Green Baboon, Defender of the Forest is special summoned and then try to negate the summon. You have to negate the Green Baboon’s effect if you want to prevent its successful summon. Rai-Oh’s worth is proven in negating Synchro summons and Dark Armed Dragon cards, not in dealing with random monsters with trigger effects.

—Curtis Schultz