You may have forgotten
Knocking enemies out is a big part of the Assassin’s Creed Odyssey: Fate of AtlantisDLC (I won’t spoil exactly why here), and odds are a lot of you are coming out of a lengthy hiatus, having completely forgotten how to do the job.
Here’s a few different approaches.
Your fists
This is by far the easiest way to knock out an enemy without killing them. Unequip one of your weapon slots using the inventory menu, then swap to your fists with the d-pad. Relentlessly attack your quarry until they’re knocked out. Alternatively you can damage them using other means then change to your fists and finish the job.
Just be sure there are no damage-over-time (poison, fire) effects on them, otherwise they’ll die.
By bow
At this point you’ll have the opportunity to invest in alternate arrows in the hunter skill tree. It’s right there on the second tier listed as “Arrow Master,” just select it once and you’re good.
To craft arrows you’ll want to go to the bag near your bow slot in the inventory menu and create away. You’re aiming for paralyzing arrows.
By way of stealth
After getting behind an enemy quietly, you can press L3 to initiate a knockout instead of a stealth kill. Note that you need to be able to do it in one go, and even at a high level the AtlantisDLC enemies might shrug it off, making it the least likely scenario.
You can actually see how much health a stealth kill attempt will chip away, so if needed you can go for the “kill” strike, then swap to fists and end it non-lethally.