Connecting with the fourth mission, Fireteam Osiris will continue chasing after the Blue Team. You’ll deal with a few Prometheans in the beginning, so clean them out, then look for a staircase to climb up, which will take you to Meridian Station.
You’ll notice the Blue Team’s Prowler nearby. Scan it real quick, and if you need a weapon pick-me-up, find the nearby Norfang gun.
From there, make your way through a doorway to the left of the staircase you came from. Some foes will be waiting, so kill these enemies and then find a nearby unit with a somewhat questionable door. Use the Spartan Charge to bust through it, and you’ll find a collectible Data Pad, along with a Railgun.
After the area is cleared out, work your way through this opened space, and continue onward through the enemies that get in your way. You’ll deal with a few Prometheans, so make sure your team is on point. A Knight will also drop in, so it never hurts to have strong weaponry like that Railgun.
Once they’re finished, keep moving along the walkway, but make sure to stay away from the lava. There will be a hole to drop down, which will take you to a nearby circle-shaped platform. Take it down to the next level and watch the cut scene.
When the cinematic concludes, you’ll have to take on the Warden Eternal, a large enemy carrying a big sword. He’s shielded and also has ground attacks you’ll want to avoid. Point to the Warden for your fire team to attack (by pressing up on the D-pad) and then use powerful weaponry like the Railgun. Hit him enough times and he’ll eventually evaporate into a black hole.
Once he’s done for, a door opens. Go through it and you’ll kick off another cut scene, concluding the mission.
Continue the adventure with Mission 6: Evacuation, or head to the free Halo 5: Guardians Walkthrough and Guide. For in-depth strategies and secrets, check out the Official eGuide and Halo 5: Guardians Collector’s Edition Strategy Guide.