魔王度診断 - Test Your Aptitude as a Demon King is a free Android game developed by Testii. The game allows you to test your aptitude as a demon king by answering 15 randomly generated questions and psychological tests. The questions are designed to evaluate whether or not you possess the qualities of a demon king. The app is ideal for those who want to kill time or those who enjoy taking psychological tests, quizzes, and diagnostics.

One of the best things about the game is that you can play it with your friends, or use it as a conversation starter. The app is also connected to Testii, a website where users can create and share diagnostics, tests, and quizzes. This means that you can play the tests shared on the website directly from the app. However, it should be noted that the app is ad-supported in order to provide free service.

Overall,魔王度診断 - Test Your Aptitude as a Demon King is an entertaining and fun game for those who are interested in demon kings and psychological tests.