One of the Dwarves that set out from Erebor with Balin to recover their ancient city of Khazad-dûm. When they arrived there, they found that the occupying Orcs were ready to defend the city, and a battle was fought in the Dimrill Dale beneath the East-gate. Ultimately the Dwarves had the victory, but Flói did not live to see it. The account of his death is found only in the battered and partially illegible Book of Mazarbul, but it seems that he slew a great enemy before being felled himself by an Orc-arrow. The surviving Dwarves buried Flói in a grave near the Mirrormere.