This challenge is aptly named as indomitable, because it is one of the most difficult challenges to fully complete. It is made worse by the fact that until the mid-season update of Season of Skulls, most kill-count challenges wouldn't stack.
This challenge is also one of the most rewarding challenges in Anthem, as it rewards with 15 Armor Parts! The only other challenge that does something similar is Endurance: Tip of the Iceberg II
Note: The original crystal rewards for this season were differently colored (beige) when compared to the regular pink color. However, they both are the same crystal rewards. The change was done to remove any confusion that might have been caused by any remaining crystal rewards from the previous seasonal event.
Additional Notes and Trivia
The "Time remaining" mentioned is only meant to represent the maximum time for the challenge to be completed when it is available.
This challenge is available only for a limited time when a full seasonal run of a Cataclysm or Festival took place. It may have repeated daily/weekly during that time.
To see the main pages that aren’t a part of the Cortex but a part of the Lore, see below: