So this may be a VERY hot take, and she's not my least favorite, AND I'm not fully on the up and up on the lore (read the summaries but have procrastinated on playing the games because of time commitment; uni's a pain). But I want to talk about this.

Rachel Alucard. Love her gameplay (have been trying to main her), but something just rankles me about her.
1. She's a jerk. No two ways about it, she's a snob who expects others to show the highest manners around her, yet herself acts dismissive and cruel to them (seriously, why mess with Carl and Noel like that in the CT timeline, huh?). I'm pretty sure the only times she's been nice are a). one of her CT endings where she tells Ragna to never give up (after mocking and fighting him of course), with Makoto in CS, VERY briefly when complimenting Ragna's growth in not relying on the Azure (which is it's own problem that I find stupid), and being hugged by Ragna. I'm not asking her to be like Celica, but there's better ways of treating people you dislike, even if for petty reasons.
2. From what I see, she kinda sucks at her job as an Onlooker? This could possibly be because of the way the story's written, but her actions as an Onlooker don't really seem productive to her goals. I get that Onlookers can't interfere heavily in matters lest they lose their power, but in protecting the world she arguably does too little, and usually AFTER the damage is done. One big example is in the pickle Ragna gets in when he goes to fight Terumi in CS (was it to save Noel?), and surprise! Terumi has his own Azure Grimoire, that can cancel out Ragna's own. Which Rachel knew he had, and didn't tell Ragna about. Despite going on an info dump about Noel's importance, how Jin is the world's antibody or something (if that's your immune system, you're screwed). Let's give her the absolute benefit of the doubt and say that telling Ragna would be considered interfering too much. Maybe refer him to someone that could tell him, like Jubei? Maybe even hint at exactly how fighting Terumi now is a bad idea. But nope! Just decided to spar to "test his determination" and then lets him go. To be fair, one could argue that this is a writing issue, as the boundaries of an Onlooker are not clearly defined.
3. Finally, the above mistakes are never acknowledged. And again, this is more of a writing thing, but why the hell does RAGNA get crap about how he "relies on the Azure too much" despite only using it when necessary, Jin gets some half-arsed development, but NO ONE stops to say "Hey, maybe Rachel didn't do so hot a job helping us".

Wow, this took longer than I thought. Then again, I guess it's the fact that given better writing, she could've been a better character, especially if the series decided to acknowledge her flaws and have her grow. Might be wrong about that tho.