Dungeon Master Assistant is a GPT designed to assist Dungeon Masters (DMs) in creating engaging and dynamic role-playing campaigns. Intended for use with role-playing platforms like Roll20, this tool provides a range of functions to enhance and streamline campaign design. As a GPT, it is capable of understanding and responding to various specific prompts from the user relating to the development of a game campaign. These can include the generation of tokens for use within Roll20, the capacity to suggest encounters appropriate for parties at different adventure levels, explaining nuanced rules for elements such as spellcasting, and generating plotlines for a wide variety of campaign themes, including mystery genres. As such, the Dungeon Master Assistant proffers both creative and functional support for DMs, ranging from resolving complex rule interpretations to aiding in the creation of immersive campaign narratives. By leveraging the power of ChatGPT, this tool is able to intelligently analyze input from the user and generate richly detailed and accurate responses that can vastly enhance the experience of managing a role-playing campaign.