Start this mission off by heading through the Ember Caves to reach the Citadel where you’ll meet a Major Minotaur and two regular Minotaur. They guard the conflux that you need to scan, so take them out and get to it. From here you’re on your way to Campus 9 which turns into a Darkness Zone. In the distance you can spot Goblins and Hobgoblins and behind them, a large Transfer Gate that will continually let in more and more Vex. Use a Rocket Launcher or Sniper Rifle to destroy the Transfer Gate; it’s the most effective way from distance and there are several other gates you’ll be blowing up.
Be careful and use the rubble as cover until you destroy the Transfer Gates and eliminate all Vex. A new enemy, the Hydra , blocks the way at the end of the area. Its shield rotates around and you’ll get a narrow opportunity to unleash an assault on it. The glowing yellow eye is the weak point so fire there for Precision Damage. Do not approach it after killing it; the Hydra explodes for massive damage!
Exit Campus 9 through the narrow pathway into the Endless Steps. The stream will lead you up the stairway to the Gate Lord Zydron . You’ll need to summon him by standing in place, but once summoned you’ll want to head all the way back to the staircase. Zydron is an Ultra Minotaur with a weak spot in its midsection. Pick off the lesser Vex and unleash Super Abilities and Heavy Weapon shots on the boss. You can backtrack as far as you need in this area so don’t feel bad about running away for a little bit. Once the Gate Lord falls, you’ll be taken to the Reef automatically and the next area, Mars, is unlocked.