You don’t have to play a single type of mission to buff up your character. Remember, you can farm Arche Tuning XP from various missions in The First Descendant, other than Sigma Sector.
In the recent update, Nexon added a bunch of new stuff to TFD, like a new character, storyline, Colossus, and new mechanics. One of those mechanics is the Arche Tuning system. The gist is that you collect Arche Tuning XP which increases your Arche Tuning level. Each level grants you points that you can assign to various buffs on the Arche Tuning page, and each one of them improves some aspect of your character (like HP, Skill Power, etc) by a tiny amount. But when added together, they result in a significant buff. It’s nothing we haven’t seen before. It is similar to Diablo 4’s Paragon Board, or a bit like Path of Exile’s “web” of skills and upgrades.
Since it is added in the newest update, along with Sigma Sector missions (where you unlock Arche Tuning in the first place), you’d expect that Arche Tuning XP is only farmed in the Sigma Sector. You’d be half-right, as Sigma Sector is the best for it, but not the only one.
Sigma Sector is Not the Only Place Where You Can Farm Arche Tuning XP in The First Descendant
Sure, you can farm Arche Tuning XP in the Sigma Sector, where it all began. But it is often overlooked that other mission types give you some Arche Tuning XP as well. Missions like Void Erosion Purges, 400% Infiltrations, and Hard Void Vessel operations. One player even compiled a handy table, showing how much XP you get from each of them.
Sigma Sector Mission (High-Risk) | 1500 XP |
Sigma Sector Mission (Normal) | 750 XP |
Void Vessel Mission (Hard) | 750 XP |
Infiltration Operation (400%) | 300 XP |
Void Erosion Purge (1-30) | 300 XP |

This was mentioned in the Patch Notes, but with all the new stuff added, it can get overlooked easily. Honestly, Sigma Sector missions are not that tough so they remain the best place to farm Arche Tuning XP, but it is handy to know that you can play other missions as well and still get some XP.