Yes, "Mirai Nikki" and "Future Diary" refer to the same series. "Mirai Nikki" is the original Japanese title, while "Future Diary" is the English translation. It is a psychological thriller anime and manga created by Sakae Esuno, focusing on a survival game where participants possess diaries that can predict the future. The story follows Yukiteru Amano as he navigates this dangerous competition, encountering various other players with unique abilities.

In "Mirai Nikki" (Future Diary), Yuki Amano develops a complex relationship with Yuno Gasai. Initially, Yuki is overwhelmed and frightened by Yuno's obsessive behavior, but as the story progresses, he begins to understand her better. By the end of the series, Yuki acknowledges his feelings for Yuno, suggesting that he does indeed fall in love with her, despite the tumultuous nature of their relationship. Their bond is central to the plot, highlighting themes of love, survival, and the consequences of their actions in the deadly game they are part of.

"Mirai Nikki," also known as "Future Diary," is primarily classified as a psychological thriller and action anime rather than a horror anime. It features intense themes of survival, betrayal, and manipulation, centering around a deadly game where participants use their future-predicting diaries to eliminate each other. While it includes elements of suspense and can be quite dark, particularly with its violent scenes and psychological tension, it does not fit the traditional horror genre.

In the anime "Mirai Nikki" (Future Diary), Yuno Gasai is 14 years old. She is one of the main characters and is known for her obsessive love for the protagonist, Yukiteru Amano. Her character plays a significant role in the survival game that the story revolves around.