Challenger Comics Viewer is a free and ad-free app that allows users to view comics, manga, books, and PDFs. The app is compatible with both phones and tablets and is easy to use. It automatically loads and displays pages without the need to click to go to the next page. Supported image file formats include JPG, PNG, GIF, WebP (Android 4.0+), and BMP. Supported book file formats include PDF, CBZ/ZIP, CBR/RAR, CBT/TAR, CB7/7Z, DjVu, and ePUB.

The app's main features include automatic page loading, zoom using multi-touch, vertical/horizontal scrolling, two display modes (Simple View and Multiple Image View), scale filters, library with covers displayed for quick access, automatic switching to the next issue when the last page is displayed, border cropping, left-to-right or right-to-left reading, customizable actions, single page and "2 page" display mode, filter to improve image quality, manual scrolling by moving finger on screen, autoscrolling by long pressing on screen, tap to go to next/previous pages, fit to width/height/screen display, multiple image preview types, option to directly access a page, history management, support for multiple languages, border display over Bitmap to easily identify each page, contrast/brightness/saturation management, screen brightness management, ability to move the app to SD Card, cached data storage in internal memory or SD Card, support for Samsung "Multi-Window" mode, and color themes.

Files can be accessed on the device or network, with supported network protocols including Google Drive, OneDrive/SkyDrive, Mega, Ubooquity, DLNA/Upnp, OPDS (beta), Windows/SAMBA/CIFS, DropBox, Webdav/Cloud, FTP, and SFTP. The app requires a phone/tablet with lots of memory and a powerful processor. Documentation and an FAQ are available on the app's website, and users can provide feedback or report bugs via email.

In summary, Challenger Comics Viewer is a versatile app that allows users to view comics, manga, books, and PDFs on their phones or tablets. The app is easy to use and automatically loads and displays pages without the need to click to go to the next page. It supports a wide range of image and book file formats and offers a variety of features, including automatic page loading, zoom using multi-touch, vertical/horizontal scrolling, and customizable actions. Files can be accessed on the device or network, with support for multiple network protocols. The app requires a phone/tablet with lots of memory and a powerful processor, and documentation and an FAQ are available on the app's website.