Effect
If your opponent controls a monster and all face-up monsters you control (min. 1) are Level 4, you can Special Summon this card (from your hand). You can only Special Summon "Doggy Diver" once per turn this way. This card cannot be used as an Xyz Material for an Xyz Summon, except for the Xyz Summon of a Warrior-Type monster.
The monster effect "If your opponent controls a monster, and all face-up monsters you control are Level 4 monsters: You can Special Summon this card from your hand" is an effect that is not classified as an Ignition Effect, Trigger Effect, Quick Effect, or Continuous Effect.
A Chain Link is not created when performing a Special Summon using the monster effect of "Trouble Diver".
"Trouble Diver" can be Special Summoned by its own monster effect if your opponent controls a monster in their Monster Zone, and all face-up monsters in your Monster Zone are Level 4 monsters.
"If this card is used as an Xyz Material, it can only be used for the Xyz Summon of a Warrior-Type monster" is not treated as an effect.
"Trouble Diver" is a Normal Summon monster. (Even if it has been sent to the Graveyard from the hand or Deck, it can be Special Summoned by the effect of "Monster Reborn".)
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