First off, neither Deathsinger has a "song" per se. Actually, once the encounter starts, the Hymn of Unraveling starts (technically both deathsingers are singing). After that starts, you have one minute to grab the relic for protection. As far as which Deathsinger to slam down on, it is whatever your fireteam decides. Typically, you do left (damage a lot but don't kill), then right (kill this one), then kill the left one. That answers your third question as well. :) Again, that is up to your fireteam and is important to establish before you start the encounter. Regarding Oryx, one person is designated the relic runner. They start in whatever platform that Oryx slams. While he is running the relic (just like in Deathsingers), everyone else is on add/Ogre duty. Ogres are the priority. Kill them ASAP. When they die, they leave a ball of corrupted light where they died. Once the runner has the relic, he jumps down and finds the Vessel of Oryx. He's a red knight with an immunity shield. The runner takes the shield and then everyone proceeds to kill the Vessel. Then, once everyone is in position and has staggered Oryx (this part is obvious while in the raid), people who were assigned a platform go stand next to their Ogre's corrupted light until it says in the kill-feed that xX420NoScopezXx had detonated a corrupted light. Once yours is detonated, BOOK IT back to the immunity shield. From there, damage Oryx until the in between phase starts. This is the "mortar" phase. Basically, run around in circles without crossing paths with anyone and you'll stay alive. Just repeat this until the next in between phase happens. Depending on Oryx's health, it'll either be mortars again or move on to Echo. If it's Echo, then there will be a big grey some near Oryx that Oryx will teleport you into. Once inside, kill the Echo ASAP!! If you're outside, just clear adds. Once that in between phase is over, repeat until Oryx disappears and comes back once more where he originally started (in the center). When he's there, light him up and collect your loot!