Can a king take another piece in chess?
The game is over when the king can not move and is in danger of
being taken. Any piece could put a king in danger of being taken.
Theoretically, a king is capable of capturing an opponent's king.
However, the opponent's king would first have to have moved into
check, which is an illegal move. Therefore, while a king can take a
king, it can never happen.
But a king can participate in checkmating an opponent's king by
contolling a square into which the opponent's king could otherwise
move.
No, there is an exception. A king cannot directly threaten another
king because they cannot ever share adjoining squares, or even any
that meet at a corner. Only a queen, rook, bishop, knight or pawn
can directly apply the attack resulting in checkmate (though a pair
of them might collect the win in the case of double check that is
checkmate).