Monomi

Usami (ウサミ Usami), also known by her full name, “Magical Girl Miracle ★ Usami”, is a magical rabbit that appears as the teacher of the students in Danganronpa 2: Goodbye Despair. She is later renamed Monomi (モノミ Monomi) without consent by Monokuma, who adopted her as a younger sister.

Personality
Usami is gentle and kindhearted. As the students' teacher, she encourages them to strengthen their bonds with each other and does not like it when they get into fights. She also emphasizes the importance of caring for the environment, prohibiting the students from throwing trash anywhere on the island. Usami, is however, an unwitting pawn to Monokuma, often the butt of his jokes. It's no surprise that she is disliked and bullied by her students, as they never acknowledge her when she tries to catch their attention.

Island Life of Mutual Killing
In the beginning of the events of the second game, Usami introduced herself to the students as their teacher, and explained the rules of their life on the island. She also showed her magic power to the students, as example she can change a Chicken into a Cow. Later, after the students gather their very first Hope-shard, Usami gather them in the beach to give them a presents, which received by the few students happily, and making them trust that they were safe and sound in the island. But Monokuma soon took over, destroyed her magical staff and left her powerless after she being executed via Monobeast.

In Chapter 1, she explained numerous things to the students, such as how the old lodge was undergoing renovation or that the beach house showers did not work. She is also aid Chiaki to guard the party that was throw by Byakuya from Monokuma. After every school trial, she successfully defeats a Monobeast, which allows the students to explore the other islands.

In every trial, she is hanged by Monokuma with a rope beside his private chair.

She was executed alongside Chiaki at the end of Chapter 5 where all of her remaining copies were destroyed.

At the end of Chapter 6, Usami briefly returns in her original Magical Girl appearance and single-handedly defeats the giant avatar of Junko Enoshima after the Forced Shutdown was activated. It is unknown exactly how she came back after being executed in Chapter 5 and this is even questioned by Byakuya after they all escape the game.

Monokuma
When Monokuma shows up on the island, he adopts Usami as his little sister without her approval. She is usually beat up by Monokuma when she irritates him, which happens often. Monokuma also likes to make fun of her. He also always punches or harms her when she bothers him.

Chiaki Nanami
Both Chiaki and Usami were created by Alter Ego. They are usually trying to protect the other students from Monokuma, as seen in Chapter 1 when they stand guard outside the old lodge together. When Chiaki accidentally kills Nagito, she is executed along with Usami.

Quotes

 * “ Hue..? ”
 * “It's a place where everybody can study in peace and harmony. That's what being a student is all about.” (Explain about the library in Second Island)
 * “In any case, you can't bweak the wules. Beside, it's fine if you want to have fun but don't forget your studies. ”
 * “ There is no need to become a famous hero. There is no need to demand the respect of others. Using such things to reproof yourself, and resent others... looking at others with jealousy. You don't have to do this. Even if others do not acknowledge it, you only need to act in a way that you can be proud of yourself! Because you yourself are your greatest fan! If you can love yourself... that love will cheer you on for the rest of your life. Love..Love..! ”
 * “ Bye bye! Everyone, please do not forget your teacher. ”

Trivia

 * Monomi talks in a very childish way, sometimes including chu sounds in her speech and replacing “r” with “w” if a word would start with “r” and pronouncing her favourite phrase “love”, as “wuv”.
 * In one of her many attempts to get Monokuma out of the island, she loses her eye, causing Monokuma to mockingly name her “Monomi”.
 * After Monokuma alters her, even her dialogue display, which originally labeled her Usami, immediately changes to Monomi (which also noticed by Monomi herself).
 * Somehow, Monomi can understand an uneasy to understand speaking. It proved when Teruteru becomes mad in the first trial.
 * In Chapter 2, after Fuyuhiko nearly dies Monomi states: “If I could save himself myself I could... but my magical stick is gone and I am close to powerless...” This means she most likely has some form of healing powers.
 * In Chapter 3, she reveals that she, along with her brother, fears mice. Specifically, the idea of them biting her ears, pointing this out after the students were talking about the locked doors of Nezumi Castle.
 * This shared trait of Monomi and her "big brother" Monokuma is meant to further develop the intentional similarities between Monokuma and Doraemon, who is known to have had his characteristically absent cat-ears gnawed off by a robotic mouse at one point and is deathly afraid of mice ever since.
 * She makes a cameo appearance in the first game during the School Mode mini game as one of Monokuma's requested backups “Warlockkuma”. If you complete every back up that Monokuma request Warlockkuma comes alive as Usami and becomes a huge easter egg and “a mess up to the time line”, according to Monokuma. She then fights Monokuma and wins, and lets everyone leave.
 * Usami/Monomi is the only character (along with AI Junko and Chiaki Nanami) who dies in the second game.