It will be a baby servitor that you have to care for and as the raid goes on it thinks you're its daddy and helps you get close to the archon. Then baby prime deceives the archon into worshipping its purple glowiness. While the archon bows before the servitor, you shoot the servitor and it explodes bringing down the archon's shields. He's a bullet sponge and each cycles requires a new servitor so we're looking at 3-4 days of raid time. But don't worry you can cheese him when he initially bows before the servitor, if everyone rocket launches the water they are standing in the game glitches out an thinks you killed him and you get your rewards. But it has to be at the same time.