List of legendary creatures (U)
- Ubume – Ghosts of women who died in childbirth
- Uchek Langmeidong – Semi human, semi hornbill creature
- Ukko – Finnish sky deity
- Uma-no-ashi – Horse's leg which dangles from a tree and kicks passersby
- Umibōzu – Ghost of drowned priest
- Umi-nyōbō – Female sea monster who steals fish
- Unclean force – Slavic mythological force
- Undead – Dead that behave as if alive
- Underwater panther – Feline water spirit
- Undine – Water elemental
- Ungaikyō – Animated mirror
- Unhcegila – Dragon
- Unicorn – Horse-like creature with the legs of an antelope, the tail of a lion and a single magical healing horn.
- Unktehi – Serpentine rain spirit
- Unktehila – Reptilian water monster
- Upinis – River spirit
- Upiór
- Ur – King of the World of Darkness, often portrayed as a dragon or snake
- Urayuli – Hairy giant
- Uriaș – Giant
- Urmahlullu – Lion-human hybrid guardian spirit
- Ushi-oni – Bull-headed monster
- Utukku – ″Underworld messenger spirit″
- Uwan – Spirit that shouts to surprise people