Unlike torrents which have community verification (comments, seeders), an index file has no reputation system. You will often download a 700MB file labeled "1080p" only to find it is a camcorder recording from a theater in 2015, or the file is missing the last 20 minutes.
You want the convenience of an "index" without the crime. Fortunately, legitimate streaming platforms now offer the same or better experience. Here is where you can legally watch Thanga Magan today. index of thanga magan