Get some good 27s and the raid will be loads easier. The first time I/we beat it, myself and a Titan were 27, and were tasked with some of the harder parts of the raid - namely the relic recovery from the portals. We would open the portals up, 2 guys on each portal area whilst me and my bud would run in and get our bosses down to 1 shot. Once we were both ready to kill our boss, we dropped him grabbed our shields and came back through our respective portals in sync. For Atheon, the things to know are - the 3 people farthest back from the boss get sent through the portals. Have a designated guy to grab the shield and use the shield whack on the mobs in the middle and have a gunslinger to golden guy the enemies immediately to help. Once you've dropped the enemies you are free to clear the oracles together. Run through the portal back to the boss One at a time! Very important you don't cluster - 1) less likely to be caught out if there is a rogue harpy, and 2) if you cluster you can teleport back through the portal and waste time and potentially miss a cleanse. Once you're out, run straight to the back wall and cleanse and then DD the boss. Repeat till you're done! Your super should be up 100% of the time after the first portal run which means the rest is easy. Once you get a rhythm it's far easier. Good luck!