She wears an Alonne Knight Helm with the Old Knight Set and wields the Bastard Sword and Hollow Soldier Shield. She can also use a lot of different weapon buffs, including Aromatic Ooze and the Gold, Dark, Charcoal and Rotten resins.
While her combat tactics are nothing out of the ordinary, she has a considerable amount of HP. Additionally, she'll constantly buff her sword with a random element and she can't be lured into climbing up the ladder used by the player to reach the area where she spawns.
It is possible to defeat Rachel by igniting one of the oil-filled containers and then kiting her around it, causing her to constantly take Fire damage until she dies.