The Destined Thief can't be blocked.
,
: Another target creature you control can't be blocked this turn.
Whenever one or more creatures you control deal combat damage to one or more players, draw a card, then
discardTo discard a card, move it from its owner’s hand to that player’s graveyard.
By default, effects that cause a player to discard a card allow the affected player to choose which card to discard. Some effects, however, require a random discard or allow another player to choose which card is discarded.
If a card is discarded, but an effect causes it to be put into a hidden zone instead of into its owner’s graveyard without being revealed, all values of that card’s characteristics are considered to be undefined. If a card is discarded this way to pay a cost that specifies a characteristic about the discarded card, that cost payment is illegal; the game returns to the moment before the cost was paid (see rule 733, “Handling Illegal Actions”). (CR 701.9) a card. If you have a
full partyA party with all four listed creature types. (CR 700.8), instead draw three cards.