Demon Keyboard Theme is a personalization app developed by Powerful Phone for Android users. With this app, you can customize your keyboard with a unique and spooky theme. However, to activate the keyboard theme, you need to install the latest version of RainbowKey.

Once you have installed RainbowKey, using the Demon Keyboard Theme is easy. Simply install the theme, open it, and it will be enabled automatically. If you don't have RainbowKey on your phone, you will be redirected to the Google Play page of RainbowKey. Install and activate the app to apply the theme.

RainbowKey provides a range of features to help you personalize your keyboard. You can create your own keyboard with your favorite pictures, decorate your keyboard with 40+ beautiful fonts and colors, and choose from 10+ built-in themes. Additionally, you can use 30+ stylish fonts to decorate your words, enjoy one-handed typing with swipe input, and benefit from smart emoji prediction with 1000+ lovely emojis. Finally, the app also offers auto-correction and word prediction, and a moving cursor feature that allows you to swipe on the space bar to move the cursor position.