Cloak and Dagger works in two steps. When you first activate it, you name the monster you want it to destroy, and then it waits for that monster to make an appearance. Due to this waiting period, you don’t want to activate it after your opponent summons or flips his or her monster face up, because Cloak and Dagger won’t do anything right away. When your opponent Synchro summons Colossal Fighter and you activate Cloak and Dagger in response to the Synchro summon, Colossal Fighter is already on the field, so it won’t be removed from play. Cloak and Dagger needs to resolve before the monster is summoned or flipped face up.

After Cloak and Dagger is activated and has resolved, when the monster named by Cloak and Dagger is successfully summoned, Cloak and Dagger’s trigger effect activates and starts a chain. If I have Cloak and Dagger face up (naming Colossal Fighter) and my opponent performs a Synchro summon that brings out Colossal Fighter, Cloak and Dagger’s effect will activate. Knowing that this will happen, my opponent isn’t likely to bring out his or her Colossal Fighter while it is being hunted by Cloak and Dagger.

Special summons that start a chain allow Cloak and Dagger to act as a surprise, with more immediate rewards. When you activate an effect that will special summon a monster, the monster isn’t special summoned until the effect resolves. When your opponent activates Monster Reborn and selects Krebons, you can chain Cloak and Dagger and name "Krebons," because Krebons doesn’t immediately pop onto the field. When the chain resolves, Cloak and Dagger resolves first and waits for Krebons to be summoned or flipped face up. Next, Monster Reborn resolves and special summons Krebons. The special summon of Krebons causes the trigger effect of Cloak and Dagger to activate, starting a new chain. When its effect resolves, it removes itself and Krebons from play.

When your opponent activates the effect of Destiny Hero - Malicious, you can chain Cloak and Dagger so it will resolve before another Malicious is special summoned from your opponent’s deck. When the other Malicious is special summoned, Cloak and Dagger’s effect will activate and start a chain. The same happens if you chain Cloak and Dagger when your opponent activates the effect of his or her Plaguespreader Zombie. It is also good to know that your opponent won’t be able to perform a Synchro summon when this occurs, because Cloak and Dagger’s trigger effect automatically starts a chain.

 The Stardust and Light and Darkness Dragon Chains
"I have Light and Darkness Dragon (LaDD) on the field and I Synchro summon Stardust Dragon. If the opponent activates a card such as Bottomless Trap Hole, my LaDD responds and its effect is chain link 2. My opponent then chains Raigeki Break as chain link 3. Would I be able to chain Stardust Dragon’s effect as chain link 4? If that is possible, then during the end phase would LaDD’s effect activate when Stardust Dragon attempts to special summon itself from the graveyard?

Another question: I have Red Dragon Archfiend, Stardust Dragon, and Elemental Hero Stratos in face-up attack position. I also have Destiny Hero - Dasher in the graveyard. In my draw phase I draw Jinzo and special summon it with Dasher’s effect. I tribute Jinzo and Stratos for LaDD.†My opponent activates Crush Card Virus, tributing Sangan. Could I chain Stardust Dragon’s effect to negate the Crush Card Virus, and have LaDD negate Sangan’s effect, or would LaDD respond immediately?"

In our first question, Light and Darkness Dragon automatically activates its effect in response to the effect of Bottomless Trap Hole, to which Raigeki Break is chained. Stardust Dragon’s effect can be chained to Raigeki Break because it is a quick effect, which is spell speed 2. When the chain resolves, Stardust Dragon negates the effect of Raigeki Break and Light and Darkness Dragon negates the effect of Bottomless Trap Hole. At the end of the turn, when Stardust Dragon activates its effect to special summon itself, Light and Darkness Dragon’s effect will activate to negate it.

In our second question, Crush Card Virus intends to destroy Red Dragon Archfiend, Stardust Dragon, and Light and Darkness Dragon. Light and Darkness Dragon’s effect activates automatically to negate it. It isn’t possible to use Stardust Dragon instead, because Light and Darkness Dragon’s effect doesn’t give Stardust Dragon a chance. The tributed†Sangan’s effect starts a new chain after the Crush Card Virus chain has finished resolving. Light and Darkness Dragon will again activate its ability, this time to negate Sangan’s effect.

I have seen this question numerous times on message boards, which seems to stem from confusion over the nature of Gorz’s special summon. Activating the effect that special summons Gorz starts a chain, and this is bad for Solemn Judgment. Solemn Judgment cannot negate monster card effects, so it has no way to stop Gorz’s effect from resolving. When Gorz’s effect resolves and he is special summoned, his special summon is considered to be successful and cannot be negated.

Solemn Judgment is used to negate the special summon of a monster when special summoning that monster does not start a chain. Synchro summons, "contact Fusions" of Fusion monsters like Gladiator Beast Gyzarus, and the special summoning of monsters like Dark Armed Dragon and Judgment Dragon can all be negated by Solemn Judgment, because they do not start a chain. That’s really the most important question for Solemn Judgment: does special summoning this monster start a chain? If it does, Solemn Judgment isn’t your answer. Naturally if the monster is special summoned by a spell or trap card, Solemn Judgment will negate the spell or trap card.