CHORUS (EU)

I was inspired by Swan931's guide to the mastery of combat achievement. At the start of the final mission, there is an endless stream of enemies. If you have completed the game and are just trying to farm for the mastery achievements, that is the best area to do so. I wasted too much time searching for random encounters working on this achievement. Restarting the final mission will save you a great deal of time and frustration.

Before attempting to farm the majority of the rites, you need to reach level 5 with the "Senses" rite. This must be done in the open world. As you go through the game, use your senses power periodically, and pick up any loot boxes that are discovered. Most of these contain credits and with enough located, you will level up this power. Small triangles appear on your hud after using the rite of senses. These are always points of interest and usually indicate an item you can retrieve. Locations with buildings or other notable scenery are good places to start as they are usually hidden behind or in things.

Once Senses is completed, replay the last mission. When the mission starts, destroy any enemies. If you are only working on mastery of rites, then destroy all of the turrets that are present. Ignore the first objectives. Eventually you will be down to just three enemy fighters that continue to respawn.

There are eight remaining rites that you need to master now. These can be done in three stages. The first stage you should work Hunter, Apex Predator, Storm, and Crash landing all at once. Use the Leap ability to jump behind the wave. Immediately zap the first enemy with the rite of storms. This will stun the ship. If it appears to heading for a collision leave it alone and let it crash. Otherwise, shoot it with a heavy laser and then the other two enemies quickly. Repeat until those four rites are mastered. This may be the most time consuming part.

The rites of Star and Blaze can be done next. Approach each wave head on. As they get close, trigger the rite of the star power. You should easily spear though multiple targets which should count for both masteries. Repeat as needed.

Finally, focus on mastery for Control and Collision course. As the three enemies approach you, cast your rite of control. You will grab one or two of the enemies. Target the remaining ship and use control to throw a captured ship at it. If you get a collision, it will count for both masteries. If you grabbed two ships, throw them both. Farm until the achievement pops. A message also appears each time you level up a mastery skill.
You can check your progress in the mastery tab in the menu.

Not a solution for the whole achievement but I hope this will help.
I was struck on level 4 1/20 Apex Predator for a long time until I saw that the goal was not to leap and kill 3.
But to leap, kill and repeat 3 times within 20 seconds.

Maybe this is common knowledge but I have no idea how I did 4 levels not knowing it.