Spoilers: Main Points about Characters + Some Events (LONG!!!)

I will go over the major characters in the novel, their main events, feelings, etc.
---- For a quick refresher, the MC/FL's real name is Elena, who is currently pretending to be Veronica, the grand Duke's daughter, and is also disguising herself as Lucia, the brown haired girl.
--Elena
On top of those two other identities that she is pretending to be, she also has another one. I don't remember if this was ever bought up in the Webtoon currently, but she has an alias called 'L' (nice Death Note reference) where 'L' becomes a successful salon owner providing various forms of entertainment with the masters of the 'new era' (Raphael is one of them). As 'L', she purchases property and basically fucks up the market for the grand duke, causing him large amounts of financial losses. The grand duke was also trying to build a competitive entertainment district called Noblesse street but her salon is much more successful thanks to the presence of the grand masters.

Elena reveals herself and her motives to several people earlier in the story than you'd might think. She pretty much just straight up tells a number of trustworthy people, such as her knight Hurelbard and her maid, May. Raphael, the painter, finds out on his own that the brown-haired girl is actually Veronica when Elena shows up to an event as Veronica and he recognizes her, and much later is told by Elena herself that she is a fake Veronica. The crown prince also pretty much finds out on his own that Lucia = Veronica due to him recognizing her. Both of these characters do not confront her about this since they didn't want to make her uncomfortable by questioning her, but they are later told by Elena herself about her identity.

--Ren
Ren currently seems like a bully in the webtoon but he'll later develop feelings for Elena. He is actually pretty smart, he figures out that Lucia is Veronica all on his own before anyone else by following Lucia to the library and finding out that Lucia is just a disguise. He also learns that the current Veronica is a fake and that the real one is somewhere else, awake. He confesses much later in the story that he was the one who poisoned the real Veronica.

I consider Ren to be one of her most important allies thanks to his knowledge on the ducal family and physical strength. Ren tells Elena that within three months, she must somehow escape the ducal house as the real Veronica has woken up (3 years earlier than Elena expected) and Elena will be killed when that time comes. More importantly, Ren has protected Elena on numerous occasions, particularly during her escape from the ducal house, she is chased after by knights and Ren shows up to get rid of them all and lets her run away. After she runs away, he even imitates the sword style of another (missing) knight from another ducal family to drive the blame somewhere else. In another instance, he nearly dies protecting Elena from an arrow and is unconscious for several days because of it.

--Crown Prince Sian
Since there have been multiple spoilers on him, I will keep this one short. He is also another important ally to Elena, and has incredible sword skills (ends up defeating Ren in a competition). He works with Elena to take down the grand Duke's illegal opium business, which made up 30% of his income, effectively further ruining the Duke's financial situation. His relationship with Cecilia is nothing special. Cecilia herself requested that she did not want to marry him and Sian understandably agrees.

--Leabrick
Despite her being an antagonist I do actually like her. She is incredibly smart but is ultimately bested by Elena and thrown out by the duke and held captive in a jail cell, going insane near the end as she bashes her head against a wall or something of the sort, and dies. I feel like she'd would be very likeable had she been an ally in the story. Near her downfall, she realizes Elena's true personality but it is too late for her.

-- Real Veronica
The real Veronica wakes up 3 years earlier than the previous timeline. She is literally a psychopath, (described literally as a "crazy bitch" by Ren), but not a very smart one. She is first introduced in an intimidating manner and will not hesitate to do whatever it takes to get what she wants by whatever means. But this is where she fails since she usually resorts to killing her enemies if things don't go her way. She might give off the impression that she is intelligent at first but then you quickly realize she is just incredibly arrogant, narcissistic, and believes the world revolves around her, making her childish as a result. She doesn't come up with any cunning plans like Leabrick. She also doesn't really have any romantic feelings towards Sian, she just wants him as she thinks that he is the only man with the status and blood that is befitting for her, but she did state the she "personally liked him" However, she doesn't hold any lingering attachments towards him and immediately hates him and wants him dead after Sian threatens her for trying to harm Elena (Veronica was trying to have Elena and the salon visiters, which is well over 100 people, to die in a mass poisoning, by having their wine poisoned. Sian notices this, tells Elena and offers to supply the wine in the name of the royal family since other wine suppliers might be bribed by Veronica).

Veronica is also pretty jealous of 'L' and her success and tries to compete with her but fails miserably. When 'L' reveals herself to be Elena, Veronica is enraged that her substitute of low status is more successful than her.

--Grand Duke
The duke is the final boss of the story. It is revealed that he is very intelligent and wants to maintain or gain more power. After his financial ruin he attempts to gain his power back by absorbing the Bastache house (Ren's house). Since the head of the Bastache family is the duke's little brother, he even captures the head and mentally tortures and brainwashes him into handing the house over to him. The head dies when Ren meets up with him.

The emperor, in a last effort to help out his son Sian, refuses to authorize the handing over of the Bastache family to the grand duke. When this happens, the duke resorts to force, and storms the palace with his knights and tries to force the emperor to sign a contract or something. The emperor, kills himself to prevent the duke from being able to do so. (Recall the royal family is basically useless and the grand duke holds the most power over them, so they cannot outright challenge the duke). The duke and his army make way towards the Bastache house after taking the dead king's fingerprint for the contract. He actually turns out to be really strong. Ren, Sian, and Hurelbard (Elena's guard), the three best swordsman of the empire had to work together and team up against the duke to take him down. The duke is killed and Veronica is thrown in jail to be executed. At the end of the story, Veronica is executed, but never feels any remorse and just continues to hate Elena and curses her until her death.

--Overall
The novel is completely translated, and is over 200 chapters long. I have already posted a link in an earlier comment I made answering any spoiler questions. If you want to start reading from where the webtoon is on, I think it is chapter 47. I know this is literally an essay but school has finished for me and I am bored. If anyone actually read this whole summary, thank you.