Hello Jam, Nechrochasm is still obtainable, but still a Year 1 Exotic. You must get the Husk of the Pit (first upgrade step) from killing a special Knight called the Blade of Crota, and these are now only found randomly by running through TDB mission Fist of Crota. It's recommend if you don't get it when killing him, just reload the mission. Check this helpful [url=http://gamerant.com/destiny-husk-pit-necrochasm-how-to-guide/]guide.[/url]