The King of Cups predicts that emotions, relationships and matters of the heart will be in the foreground. The King of Cups indicates that we have the experience and the maturity to deal with emotional matters efficiently, unless he's ill-dignified. The King of Cups is the protector, the family man, but in his negative manifestation, the he can become, cold, manipulative and cruel. The Justice, being the card of cause and effect, brings clarity and allows us see the motives and the consequences of our actions, as well those of others.
The elements of the cards are Water (King of Cups) and Air (Justice). This is a favorable combination when our goal is to find a balance between feelings and logic, between what we want to do and what we should do. The Justice, being a Major Arcana card, will amplify and emphasize whatever traits (positive or negative) the King decides to use.