Lempo is the ancient Finnish devil who, with the help of his two demon cohorts, Hiisi and Paha, brought down the hero Väinämöinen. Within the trans-Neptunian triple system, the satellite (47171) Lempo I was discovered on 2001 Dec. 8 by C. A. Trujillo and M. E. Brown using the Hubble Space Telescope (HST), and is named Paha. The primary was identified as a binary by S. D. Benecchi et al. through re-analysis of the HST data originally obtained by Trujillo and Brown. Lempo refers to the larger component of the central binary and Hiisi to the the smaller component.