This study introduces a comprehensive taxonomy for categorizing participants in Alternate Reality Games (ARGs). The taxonomy emerges from a meticulous analysis of player motivations and behaviors within a self-designed ARG project. By scrutinizing game website logs, chat group interactions, and employing a player motivation questionnaire, this mixed-method exploration sheds light on player behaviors and motivations, based on dimensions of autonomy, competence, and relatedness. Through this inquiry, distinct player typologies within ARGs are unveiled, unveiling behavioral intricacies and motivational drivers. This research contributes to a nuanced comprehension of the unique realm of ARGs, offering insights valuable to both designers and scholars. By enhancing our understanding of ARG dynamics, this study provides a foundational resource for future design endeavors and scholarly pursuits in the realm of alternate reality gaming.