Fin is a troll in a legend from Kalundborg, Zealand, Denmark. The legend tells how Esbern Snare was building a church in Kalundborg. It was hard work, and a troll, who was passing by, offered his services. Esbern accepted; however, the troll's condition was that Esbern should be able to figure out the troll's name by the time the church was finished; if he could not, the troll would take his heart and his eyes.
en.wikipedia.org/wiki/Fin_(troll)
WTF?