Mission 5 - Unconfirmed: Halo 5 Guardians Guide
After getting down from the Pelican, Fireteam Osiris needs to Locate the Blue Team along with Master Chief at Apogee Station. Let's check out what adventure Apogee has for both the Spartan Teams in Mission 5: Unconfirmed.
Once you get down from the Pelican, you need to head towards the Apogee Station where you'll encounter few Prometheans. After eliminating them head towards the staircase and climb up to Meridian Station. Don't forget to refill you ammo before you move ahead.
You'll encounter Blue Team's Prowler upstairs and if you want you can change you weapon with Norfang gun. Now get ready to face some bundle of Enemies. Stick with the team and take them down one by one. After eliminating these soldiers head towards the open space and take down few more Prometheans along with a Knight on your way towards next section.
Note: if you come across a suspicious door upstairs then do use the Spartan Charge to go through and get the hidden collectible.
Keep moving forwards to the marked destination and try avoiding the lava. Now drop down on the lower level, move ahead to the last checkpoint and the cutscene will start. Once the cutscene is over you be prepared to face off the bunch of enemies and Warden Eternal who is well shielded and carries a powerful huge sword. You and your team need to take him down.
You need to use a powerfull weapon like the Railgun to damage him enough to make him evaporate into the Black hole. Later the door will be opened and another cutscene will begin andend of Mission 5: Unconfirmed.