Complex sentence: A Kingdom of Ends is composed entirely of rational beings, whom Kant defines as those capable of moral deliberation (though his definition expands in other areas) who must choose to act by laws that imply an absolute necessity.
Split into simpler sentences: A Kingdom of Ends is composed entirely of rational beings, whom Kant defines as those capable of moral deliberation (though his definition expands in other areas). In order to be a part of the Kingdom of Ends, these rational beings must choose to act by maxims that imply an absolute necessity.