“Chain Destruction” destroys the cards in the hand and the Deck that it sends to the Graveyard.
“Chain Destruction” is a targeting effect.
A player may target his or her own summoned monster with “Chain Destruction.”
Monsters Special Summoned face-up by monster effects may be targeted by “Chain Destruction.”
If “Chain Destruction” is activated in response to a Fusion monster being Special Summoned and that Fusion monster has less than 2000 ATK, all other copies of that Fusion monster in the affected player’s Fusion Deck are destroyed and sent to the Graveyard.
If the ATK of a monster is increased above 2000 in a chain to the activation of “Chain Destruction,” “Chain Destruction” still resolves properly.