Ok, so i've found an easy level to grind this on. If you do this on your first playtrough, you will also unlock
In order to perform a
Helix Kill, first you have to fill you Helix Bar (the thin bar that's underneath you're health segments) by collecting those rotating cubes that look like
Animus Shards but instead of being white, they are purple and on the map, they are those DNA icons.
After filling up the bar, it will change color to red and now, when you counter (
+
or
+
depending on the position of the enemy that attacks you) and press both
+
, Shao Jun will enter in some kind of rage mode where each of your strikes are assassinations. Do this in any level you want but I found
Memory Sequence 9: An old friend as being the most eficient. After the part with the Concubines, you'll get to the waterfall part of the sequence and here you have 3 enemies that after you get spotted, will stay pretty close to eachother. Kill these 3 enemies with the Helix Kill ability and restart checkpoint. Don't advance cause the rest of the enemies will be on platforms and will probably kill you. So just kill those 3 and restart checkpoint.
Below, i've attached a personal video on showing how i got it
Cheers mates and also, if you vote negatively, please leave a comment saying how can i improve this solution
Edit 17/04/2021
Important tip from
General Wizzard that I forgot to mention “you don't unlock Helix Kill until after you beat the game. Need to start the mission on Plus difficulty or higher”
Happy achievement hunting