Hito o Katte ni Sanbou ni suru n ja nai, kono Haou.: Game Sekai no Hourikomareta Otaku no Kurou

Enoshima Miyu is a college student and game otaku who has suddenly found herself in the world of an RPG she would do speedruns of. When she inadvertently utters her knowledge about the game's plot progression, she is captured by Adalbert, the handsome ruler of the animal-eared race. From there, she is forced to become their advisor...

There's no other way about it... I'll pass off my game knowledge as "prophecy," and avert the country's destruction alongside the king.