Kendra is an assassin working for Sinjin's gang. As part of his quest to wipe out the gang's activity in Goodneighbor, Kent Connolly instructs the Sole Survivor to find Kendra and take her out. The Survivor, dressed the Silver Shroud, tracks Kendra to her hideout at the Water Street apartments, fights past her bodyguards and confronts her in her room. Kendra dismisses the player as a loony, tells them that they're "in way over their head" and attacks them, though she ultimately ends up getting killed.
At the time of her death, Kendra had just received instructions from Sinjin to assassinate a scavenger named Shelly Tiller. If the Survivor chooses to do so, they can complete the assassination and get paid for it via a dead drop.
Before talking to Kendra, one can pickpocket all her ammunition. She will then use her fists in the fight and it will be much easier. Alternatively, you can reverse-pickpocket grenade into her inventory.
Kendra spawns as a leveled Gunner boss. As a result, she will most likely be the toughest of the named NPC enemies encountered in "The Silver Shroud" sidequest, as the other named NPCs in the quest spawn from the weaker Raider stat template. However, unlike the other named enemies in the quest, she is confronted alone instead of alongside henchmen.
A well tossed frag grenade from the bottom of the stairs will take care of the turret at the end of the hallway before reaching Kendra's door.