Halo Wars 2

In order to unlock this achievement, you will need to complete all six objectives (three Optional and three Bonus) and earn a gold medal on Legendary in the second mission of the DLC, "Not On My Watch." Unfortunately, you must do this all on one playthrough of the mission.

With  this in mind, please see below for the mission's Par Time and Optional/Bonus Objectives.

Par Time

• 45 minutes

Optional Objectives

• Finish the mission without losing any Colossus units
• Destory Banished Forerunner ship supplies
• Disable Controller Sentinel shields [0/4]

Bonus Objectives

• Destroy enemy units and buildings with the Colossus Stomp [0/15]
• Kill Goliaths [0/10]
• Kill the Hunter Captain within 3 minutes

For additional notes, please continue reading below.

Additional Tips

• Try to complete the mission within 2-3 minutes of the Par Time; the Par Time bonus at the end is important
• Save often throughout the mission and reload if you are losing too many units; the less deaths you have, the higher your combat bonus will be at the end
• Ignore the Phoenix Logs, they are not important
• Focus on building/upgrading Hornets and Nightingales units throughout the entire mission
• At the end of the mission, when the Hunter Captain teleports away, make sure to move your units away, otherwise the area of effect attack will destroy and kill your units.

For an in-depth walkthrough of this mission, please refer to multi-step guide below.

1. Once you are required to build a base and mech pad for the Colossus unit, choose the base to the southwest (this direction is given assuming you did not rotate the map from the beginning of the mission).
   • On the way to this base plot, your ODST unit will pass an Energy Node. Capture it, then move on.
2. Once the base and mech pad have been built, move the Colossus east towards the Capture Point. The ODSTs can stay at the HQ for now.
   • There are a two sets of Banished supply buildings on the way to the Capture Point. Make use of the mech's Stomp ability to destroy these buildings, making progress towards the first Bonus objective.
3. After the buildings have been destroyed, move the Colossus to the Capture Point but do not stomp on the base plate yet; instead, begin reinforcing your HQ. You should build three Supply Pads and two Generators. Then build two Turrets at the entrance of your base (one of them should be upgraded to Anti-Infantry and the other should be upgraded to Anti-Vehicle).
4. Once building is underway, run out the clock for a few minutes as a means of stockpiling resources.
5. Begin using your Leader Points to unlock Restoration Drones and Scatter Bomb (I and II).
6. Begin upgrading your buildings in this fashion:
   • Upgrade Generators
   • Upgrade Supply Pads
   • Upgrade HQ to Level 2
   • Build Air Pad
   • Build Armory
   • Upgrade "Advanced Logistics" at the Armory
   • Upgrade Air Units
   • Upgrade "Reinforcements" at the mini-base
7. When there are around 8 minutes left on the clock, use the Colossus' Stomp ability on the Capture Point's base plate. Now move the Colossus back to your HQ.
8. Build 2-3 Nightingales and 6-8 Hornets.
9. Build two Turrets at the backside of your HQ. Upgrade one to Anti-Infantry and one to Anti-Vehicle.
10. Move your army west and destroy the Banished mini-base. Build your own mini-base here with two upgraded Generators and two Anti-Infantry Turrets.
11. Continue building Hornets and Nightingales at your HQ. You should have 4-6 Hornets for every 1 Nightingale. Also, focus on upgrading your HQ to Level 3, then upgrading everything left at the Armory. Once there are no more Armory upgrades left to build, destroy the building and replace it with an upgraded Supply Pad.
    • Try to leave 1 Nightingale and 2-3 Hornets at the HQ since Banished Infantry units will often attack your base. The Air units will help supplement the firepower of the upgraded Turrets you've already built.
12. With your main army, begin moving northwest around the edge of the map.
    • You will essentially be moving in a giant clockwise circle around the edge of the map during this mission.
13. Along the way to the second Capture Point, make a pit stop to shut down the first Controller Sentinel shielding generator. Without its shields, you can use a Holo Decoy to distract and destroy the Sentinel.
14. After taking out the Sentinel, move to the second Capture Point.
    • At each Capture Point, there should be 2 Goliaths (sometimes, there's only one Goliath at this second Capture Point).
15. Kill the 1-2 Goliaths here and shut down the Capture Point.
    • During your circular march around the map, make sure you are making quick pit stops with the Colossus unit to "stomp" on Banish supply buildings.
16. Continue moving northwest. When you reach the northwest corner of the map, destroy the Banished base and build your own. Fill this base with upgraded Supply Pads and four Anti-Infanty Turrets.
    • During your march, make sure you are upgrading Air Units back at your main HQ (specifically, the "Wingmen" upgrade).
17. Continue to move your army past the light bridge towards the third Capture Point. Kill any and all Goliaths here (most of the time, two will spawn, but there have been instances where a second set of two will spawn).
18. After shutting down the Capture Point, continue moving east (or north, if you rotated the map). Shut down the shielding generator and then distract and destroy the Controller Sentinel. Continue marching east towards the fourth Capture Point.
19. When you arrive, you should be greeted by 1-2 Goliaths. Kill them and then shut down the Capture Point.
    • Remember to utilize the Colossus' Stomp ability to destroy Banished buildings for the first Bonus objective.
20. Continue moving your army southeast around the map. Your next goal is to shut down and destroy the final Controller Sentinel. Once that is done, gather your entire army at the nearby light bridge that leads into the center of the map. You no longer need to keep any Nightingales or Hornets at your main HQ.
21. With your army fully upgraded and healed up, cross the light bridge, enter the center of the map, and begin laying waste to the Banished forces. Make sure to destroy the Forerunner supplies laying around the center of the launch pad in order to complete the second Optional objective.
22. Once the area is cleared of enemies, make a manual save. Now activate the terminal.
23. The Hunter Captain boss will appear after shutting down the launch sequence. Move your Colossus and ODST units to a safe area, and then attack the Hunter Captain with your near-immortal army of Hornets and Nightingales. You will need to move quickly with your Air units since there is an objective to defeat the boss within three minutes.
24. Once the Hunter Captain hits 75% health, he will teleport a little bit and be protected by three Goliaths. Kill the Goliaths quickly and then focus fire on the Hunter Captain. When the Captain hits 50% health, he will teleport again and another three Goliaths will spawn. Again, kill the Goliaths and then finish off the Hunter Captain.
    • If, at any point in the fight, the 3-minute objective pops up as failed, reload your checkpoint and retry the boss fight.
    • The reason the Colossus unit was kept away from the fight during this time was to ensure it was not destroyed for the first Optional objective.

If everything went according to plan, you should have finished the mission between 42-46 minutes with all six objectives completed. Even without any score-increasing skulls activated, you should net a comfortable score for the gold medal score.

All in all, with every Optional and Bonus objective checked off, and a gold medal obtained on a Legendary playthrough, the achievement will unlock.