And the reason that pigs sit in mud instead of water is because an author of a book needed an animal to be away from the water for some sort of plot exploit.
It is true.
Even the Satan is also an employee in His kingdom. This creation is created by Him for His entertainment. In a cinema, not only the hero is remunerated but also the villain. Satan is used to test the devotees through his attractions. Thus Satan is required in the spiritual effort of the human being. In answering a multiple-choice question, there are three wrong answers along with one correct answer.
The three wrong answers represent Satan, which appear more correct and attract the mind. The power of discrimination of the student becomes more significant in presence of such wrong answers only. What is the significance of the happiness without misery? Nothing and none can oppose the Lord. Satan is required for His divine game.