This is a chapter specific trophy available in R-03, this is one that is much simpler if attempted after already finishing the game once (or just beating Monsoon) this is because, through combat, it is significantly easier after obtaining a few more Fuel Cells along with Ripper Mode and the Sai weapon.
To obtain this via combat after finishing the game you'll want to activate Ripper Mode and use your Sai on a Mastiff, as long as it's on Normal/Hard it should put them into a state where you can Zandatsu them and immediately regain your energy to do it again to the next Mastiff (I'm not sure whether Easy would kill them immediately as I have not actually played on Easy). This is also a good option because once in combat you get the nearby area lit up slightly allowing you to navigate a lot easier, it's also quicker and you don't need to worry about messing up.
If you choose to do this first playthrough with combat it may take longer to fight off the Mastiffs but they are fairly slow in their attacks and thus easy to Parry, they are also easily beaten down with the staff which you'll have earned after Mistral, again, you'll get the benefit of vision.
If you choose to take this with stealth (not advised but still possible, just difficult without any sight), you'll want to start off taking a left until you can go no further, after this climb the train and stand above the Mastiff below and wait until you cannot see the Mastiff on the rights eyes anymore, this means you are safe to Ninja kill. Once you kill that Mastiff run to your left and keep going straight, if you did the first part in the first cycle (which is not hard as it's a fairly long cycle) the Mastiff in the next section will not be able to see you yet so just keep running, you'll need to fight some Dwarf Gekkos but the do not alert the Mastiffs, keep running forward until you see a Mastiffs eyes in the distance, at the point turn left and Ninja run up one ledge (do not approach the 2nd yet). Go as far right on the ledge as possible and wait until you cannot see the Mastiff, go up the ledge and take approximately 5 or so steps left, run forward until you hit a wall then go right until you hit a wall, you'll have avoided detection and will be a couple of steps from the exit.
Again I must advise that combat is the smartest way to do this as you have the gift of vision but it's entirely possible to do so with stealth.