This guide will tell you where to farm the Axi Relics in Warframe.
You can go to get Axi Relics first is Marduk in the Void; it is a sabotage mission that can drop Axi or Neo Relics as a completion reward.

The next place you can farm for Axi Relics is on tier 3 interception missions, Xini on Eris, Berehynia on Sedna and Cerberus on Pluto. It can drop as A, B, and C rotation rewards that you can get on rounds 3,4,7,8, 11, 12, etc.

The next place you can farm Axi Relics at is Apollo on Lua. It is a disruption mission, but it is not recommended to farm from this mission if you’re newer since the enemies you need to kill will be a bit tanky. You will need to kill them relatively quickly, Axi relics will drop as B and C rotation rewards from the mission.

To get the Axi Relics every round, you will need to get either B or C rotation rewards every round. You will need to defend all four conduits on round 1, and defend three conduits on round 2. On round 3 you can either defend just two conduits for B rotation rewards or defend 4 for the C rotation rewards.
On rounds 4 and up, you only have to defend one conduit for B rotation rewards and 3 for C rotation rewards.
