[Fate Crossover] The Holy Grail War of an Interstellar Competitor

"Young Assassin, you've been studying here for three years. The world of Assassins needs fresh blood, soaring through the skies like an eagle. However you look at it, you need to achieve greater things than those who came before you. You think so too, don't you, Shirano?" Mentor Guda-kun spoke sternly to X, while their companion Zabi-kun could only offer a helpless smile. "I don't expect you to be like me and get seven or eight Holy Grails from those middlemen at the Grand Time Temple. Let's start with a small goal: get the Greater Grail of Fuyuki!" With dreams of surpassing her mentor and becoming the strongest Assassin, and the Greater Grail as her goal, Mysterious Heroine X makes her entrance! Wait... Hold on, what do you mean the Grail was stolen by Yggdmillennia? My mentor never said I'd have to fight in Romania!