Halo Wars 2

This achievement, as well as "Freeze!," may come naturally during your online career while playing as Serina. That being said, both of these can be done with minimal effort in a 3v1 Skirmish match against the AI on Legendary. If you prefer to knock these out this way, head into the Skirmish lobby and make these setting changes:

• Map: Sentry
• Gametype: Strongholds
• Starting Supply: 9999
• Starting Power: 9999
• Fog of War: Off

Now choose Serina as your leader and begin the match. Once the match starts, begin building Frostravens at your HQ and allow them to sit in place when they come out onto the battlefield. Soon after the first handful of Frostravens are built, the enemy will eventually have reached your base (or be on the way) and begin attacking your HQ. It is at this time that the aerial units will begin to freeze the hostiles.

Now open the Leader Ability Menu and unlock/use the Seismic Blast ability on the frozen enemies. You should be able to shatter/kill anywhere from five to ten enemies depending on their grouping patterns. Simply repeat this process a few more times throughout the match when the enemy approaches your base. Soon enough, you will unlock "Freeze!" for freezing fifty units and "Insult upon injury" for shattering twenty units.

NOTE: Rather than utilizing the Frostravens to freeze enemy troops, you can also use the "Cryo Bomb" Leader ability. This ability will freeze enemies much quicker, and with Fog of War turned off, you can freeze enemies anywhere on the map where they are grouped up, rather than waiting until they have reached your side of the map.