In Ancient Greek myth, Nemesis was the goddess of divine retribution against those who succumb to pride and arrogance. Also, she is the daughter of Erebus and Nyx.
It is also believed that Nemesis produced the egg from which hatched two sets of twins: Helen of Troy and Clytemnestra, and the Dioscuri, Castor and Polydeuces. The reason they hatched from an egg is because, in order to avoid Zeus, Nemesis turns into a goose, but he turns into a swan and mates with her.
One of her acts of retribution was to punish the beautiful Narcissus for spurning his many suitors. Nemesis caused him to fall in love with his own reflection in a pool of water, which led him to perish there from despair and regret.
Nemesis appears as the boss of the Nemesis Tower in the Snow Queen Quest, and is the Persona of Michiko Matsudaira. As a ploy to stall for time, thus allowing Nemesis to grow in power as the tower's prisoners are tortured further, Michiko gets rid of the time limit for her tower. Either way, when she is found, Michiko transforms into Nemesis with a speech saying to "Lord Nemesis... Be the shield that protects me!" and "Be the sword which vanquishes my foe!".
DemiKids Light & Dark
"An inscrutable demon whose vengefule nature is legend among those who've felt his wrath."
Nemesis has the power Fog LV, which makes dodging attacks easier. The power levels up the more he fights.
Stats
Megami Ibunroku Persona
Nemesis' stats are dependent on the order in which the towers are conquered and in how much time the party takes to arrive to her. Stats are listed in this order: Nemesis Tower is the first or second tower visited, took less than 20 minutes to get to the boss; Nemesis Tower is the first or second tower visited, took less than 1 hour to get to the boss; Nemesis Tower is the first or second tower visited, took more than 1 hour to get to the boss; Nemesis Tower is the last tower visited, took less than 20 minutes to get to the boss; Nemesis Tower is the last tower visited, took less than 1 hour to get to the boss; Nemesis Tower is the last tower visited, took more than 1 hour to get to the boss.