According to Marx, what would be be the main characteristic of communism?

According to the political ideas of Karl Marx communism has several main characteristics.

Class struggle is a main characteristic of communism, the existence of a people where economics and monetary status are meaningless as all rely equally on one another's skills and contributions.

Elimination of private property and means to produce goods, private property and a classless society cannot exist harmoniously, thus communism cannot develop. As a result, private property and the ability to reproduce it must be eliminated when trying to create Marxist Communism.

Transition to Socialism, while Marx does not agree with Socialism on its own, he argues in order for a true transition to communism a stage of socialism is necessary.

Marxist to Leninist Communism, Marx argues that a communist revolution is unavoidable following the conditions mentioned above and that no outside action is required, however, later followers like Lenin believed revolution must be prompted by action.