The Warrior
In a single life, defeat Fallen in Eventide Ruins.
Phylaks was ordered to take control of Vex territory on Europa. By defeating her soldiers patrolling the outskirts of the Fallen city, you should be able to discover intel on her location.
"These Eliksni are most loyal to Phylaks. You must cut through them if you wish to reach their leader." —Variks the Loyal