Make sure to combine this achievement with this other one if you're not boosting it in Blitz:
The Cataclysmic achievement in Halo Wars 2 worth 35 pointsKill 50 units with Cataclysm (Multiplayer, Skirmish, or Blitz)
This achievement will just take a long time and be quite boring, unless you can find someone to boost it in Blitz.
If you have a boosting partner it will be far easier and faster!
Simply make a deck for Voridus that includes the Invigorating Frenzy card and at least the Infused Engineer(for infusion drops), start a private Blitz match, and avoid capturing the center point. Take the energy drops, and spam skipping the cards until you get the Invigorating Frenzy. You'll only be able to use it if you have Infusion on the battlefield so use the Y ability on the Engineers to drop infusion. That will be a far faster method but does require a boosting partner!
Otherwise, if you can't find a boosting partner, you can get it this way in 2 Strongholds matches.
Start a Strongholds match with these settings:
Game Type: Strongholds
Time Limit: 30
Starting Pop: 60
Additional Pop/Stronghold: 10
Unit Ability Cooldown: 200%
Fog of War: OFF!!
Leader Powers: On
Required: EMPEROR!!(powers recharge 2x fast)
Optional: Sugar Cookies(50% extra HP)
Enemy AI: Easy, Cutter's a good choice.
Start the strongholds on any map you choose, although Sentry will probably work well.
Once the match starts...
1. Go around and build all the Strongholds
2. Set a global rally point nearish the enemy base, in the front of it to try to block the units they'll produce
3. Use these leader powers asap: Voridus Assault Pack and then you can start using Invigorating Frenzy because the Assault Pack starts spewing infusion EVERYWHERE....
3. Queue up a bunch of grunt squads and engineers from nearby bases, and Voridus from your main base, make sure they all go to the global rally point
4. Watch the fight and wait...
5. For the leader power countdowns to trigger
6. With Emperor Skull Invigorating Frenzy will take ~ 1:10, Cataclysm ~ 1:45, Infusion Wake ~ :55, and Voridus Assault Pack ~ 1:20
7. Use Invigorating Frenzy asap each time
8. Cataclysm will take 5 minutes to trigger at the start of the match.. use Infusion Wake right before Cataclysm to cause the most damage, spread infusion EVERYWHERE, the Infused Blisterbacks are amazing for spreading infusion also
9. You'll easily get the achievement for 50 Cataclysm kills done in one 30-minute match if you're smart with the infusion spreading...
10. Repeat another match for the rest of the missing Invigorating Frenzy uses