Nero Claudius? Oh man, that's a fun one to unpack. She's not exactly the Nero you read about in history books, that's for sure. In 'Fate/EXTRA' and its sequel 'Last Encore,' she's the Saber-class Servant you, as the player, can contract with. The whole thing is set in this bizarre virtual Holy Grail War, so the rules are already a bit off. She's presented as this flamboyant, self-proclaimed 'Emperor of Roses' who's convinced of her own perfection and artistic genius, which is a hilarious twist on the historical tyrant. It's a classic 'Fate' move—take a vilified figure and reimagine them through a more sympathetic, or at least more complicated, lens. Her role is fundamentally that of a protagonist's partner, but her personality completely dominates the dynamic.
Her story in 'Last Encore' gets even weirder, dealing with failed timelines and a decaying digital world. She's less of a straightforward heroic ally there and more of a persistent, almost tragic force of will. I've seen some fans argue she feels redundant next to Altria, given they're both Sabers with regal backgrounds, but I think that misses the point. Nero's entire deal is performative confidence masking deep-seated insecurities and a desperate desire for love and recognition. Her 'Imperial Privilege' skill, which lets her temporarily claim almost any skill, is a perfect metaphor for that—she's literally faking it until she makes it, which creates a different kind of narrative tension compared to Altria's more stoic burden of kingship.
Honestly, whether you find her endearing or insufferable probably depends on your tolerance for her particular brand of theatrics. I bounced off her at first, but she grew on me after seeing how her story plays out in the game's bad ends, where her fragility really shows.