If a diabolical villain threatened to blow up a city unless you kill one innocent person, what would a kantian say you have to do?

The answer would be, kill the innocent person if they would die in the city anyway.

Immanuel Kant was a German philosopher whose theories are referred to as Kantianism.

According to the morality of Kant the good aspect or bad does not depend on the consequences of an action performed, rather it is dependent on whether we fulfill our duty or not.