Marune is a free Android app designed to help martial arts enthusiasts track their training progress and stay connected with their friends. This app allows users to record their training sessions, seminars, camps, at-home exercises, and more. Users can also keep track of the techniques they trained, check-in at every school they train, add their total trained time and sparring time, and attach notes and photos to each activity. Additionally, the app enables users to save their competition results, record their tournament history, log their wins, losses, and rank, and add notes and photos to their tournament post.

Marune also features weight and Gi tracking. Users can set weight goals for competitions, weigh-in, and track their progress. They can also add the Gis they own in the new Gi Keeper tab, tag each activity with a Gi, and see stats about their usage. The app allows users to share summaries and pictures of their trainings and competitions on Marune or send them to Facebook and Instagram. Users can connect with their martial arts buddies, share their journey with them, comment on their activities, and reply to comments on their activities or give praise through "OSS".

Overall, Marune is an excellent app for martial artists who want to keep track of their progress and stay connected with their friends.