To unlock the For Love of Persia trophy in Assassin's Creed Odyssey, you must first purchase the third episode of Legacy of the First Blade (or own the Season Pass) and download Episode 3.
You will unlock the Fury of the Bloodline warrior ability after completing a quest called A Flight in Fire quest early in the Episode 3 DLC. You will need 1 Ability Point to acquire it and can use two more ability points to upgrade it. Don't forget, you can re-spec your character by holding L3 if you don't have any skill points to spare.
Fury of the Bloodline: Unleash a flurry of 5-6 attacks against a single enemy, each dealing 120%-150% Warrior Damage. Generate 3-4 Adrenaline segments.
Now you just need to kill 10 enemies with this skill, which you will need to assign to one of the D_Pad buttons. Hold L2 and press your chosen face button once to activate the skill and take out a total of 10 enemies to unlock the trophy.
You might find that you don't get a kill on stronger enemies with the ability. You can use weapons/engravings that increase Warrior Damage to increase your chances, or you can, of course, weaken enemies first before using the ability.