Mara or Marena is one of the main goddesses in Ukrainian mythology, the legends and myths about which have survived to a greater extent than about many other deities.  She was not the opposite of the goddess Lada, rather she was her equal.  The goddess was described as a beauty with an outstanding appearance.  Dark-haired, pale and slim, she was the personification of dignity and feminine strength.  She is the goddess of evil, night, horrors, gloom and disease.  Mistress of the Underworld is Navi and Mistress of Death.

 It should be noted that Slavic mythology was not as simple and primitive as it seems to us now.  All concepts of dark and light deities were not divided into categories of good and evil.  Our ancestors knew how to look deeper into the meaning of things and search for truth even in such concepts as life and death.  In pagan mythology, there was no relationship between "night" and "death" with something 100% evil.  After all, this is not the end point, but part of the cycle.  After every night comes a day, after every winter comes spring.  And after death — rebirth.  So the goddess Mara, like all these phenomena, was not the personification of evil, but an important part of the harmonious universe.