Raynesia

Rayneshia El-Arte Corwen ("Lenessia Erharte Cowen" in the Crunchyroll translation of the anime) is a member of clan Corwen, the most prestigious clan in the East. She later becomes the Ambassadress of the League of Freedom Cities Eastal to the Round Table Alliance in Akihabara.

Female nobles don't have any real authority and instead exist for political marriages, which is why she is so lazy and unmotivated, since she knows that she will never be in a position to do anything worthwhile and her only is role is to just look pretty and perfect. However, because of the May Incident, those pre-established societal rules are challenged by the Adventurers.

Appearance
Rayneshia is well-known for her beauty, although that tends to irk her because she is aware of her position, which essentially required her to look pretty and nothing else. Her attire is left up to her personal maid, Elissa, since Rayneshia herself prefers to wear comfortable pajamas which are unacceptable for social events.

Personality
She is laid-back, gloomy, and lazy to the core, preferring to do nothing but eat, daydream, and nap for the entire day. Nonetheless, being raised in a royal family, she knows how to act properly in society and to control herself in front of others -- however, it is likely because of this that she is so apathetic towards her surroundings. Rayneshia proves to be very judgmental of herself, calling herself "lazy, cowardly, and irresponsible," and thinks to herself that she isn't as smart as she would like to be.

Whenever she daydreams in the public, due to her beauty, people misinterpret her behavior as being concerned about the future, and thus she has the nickname "cultured lady with a sense of sorrow." She only acts as herself in front of Krusty, who she realizes can see right through her facade, and Elissa, who has been serving her for a long time.

Given all of her shortcomings, she can be quite bold and straight to the point when a problem must be solved. For instance, when an army of 20,000 Goblins began invading cities, she voluntarily traveled to Akihabara to ask for aid from Adventurers while most nobles were still bickering among themselves about how best to exploit the Round Table Alliance to their advantage. When Lord Marves pays an unexpected visit, she manages to rein in her emotions even when he treats her as nothing but decoration and rags on her for losing his letter.

Because young noblewomen, especially one from such an influential family like the Corwen clan, were highly scrutinized, girls were strictly educated on how to act like proper noblewomen from a young age. Rayneshia was no exception, and Elissa suspects that it is for this reason that she has few friends her own age. On top of that, she had practically given up on making friends, so she adamantly insisted that the tea parties she went to with the Adventurer girls were too much work.

Conference of the Lords arc
Rayneshia and Elissa appear before Duke Serjiad Corwen when the spies in Akiba return.

Rayneshia, Fuevel, and Appletta are debutantes when representatives of the Round Table Alliance arrive at the Ancient Palace of Eternal Ice to attend the annual Conference of the Lords. Finding his opportunity to worm his way out of stifling conversations with the Lander nobles, Krusty quickly becomes her acquaintance, to her mild displeasure. However, seeing how free he was to do whatever he wanted, unlike her, she came to admire both him and the Adventurers.

Return of the Goblin King arc
Rayneshia was told by her father to stay at the Ancient Palace of Eternal Ice with her Grandfather due to the invasion of Goblins and Sahuagin as a result of the Return of the Goblin King event. However, because the nobles took too long over bickering on how to use the Adventurers to their advantage, she defies her father's commands and goes to personally plead for the Adventurer's assistance against the goblin hordes. Her outlook on social classes was completely turned upside-down as she witnessed how well-educated the Adventurers were in comparison to the military officers and nobility of the People of the Land. Her impassioned speech to the crowds convinces Krusty and the other Adventurers to lend their aid.

Libra Festival arc
Because she acted entirely on her own without the authority of the Nobles, she was forced to shoulder all the responsibility, and had to go to Akihabara to become the Lander ambassador to the Adventurers. Ironically, Krusty tells her that since Adventurers don't care about politics, she gets to just laze around all day long, exactly what she wanted much to her happiness.

When she shortly realizes that she's now swamped with requests between the Guilds and Landers and now barely even has time for herself. She feels that she got conned by Krusty as a result.

Fallen Guardian arc
Rayneshia finds herself swamped by those joining in on her "tea party," Adventurers that were assigned to protect her while several of the Round Table Alliance's guild masters were away on various missions. Maryelle in particular takes great joy in dressing her up, while Rayneshia admires the stoic Rieze.

However, learning about the murderer makes her tense, and even more so when she learns from Kunie clan member Kinjyo that this murderer is actually one of the Royal Guard. Although she contemplates turning off the magic circuit that allowed the Mobile Armor to operate, she falters upon learning that it would also end the Guard system and cut off Akiba's protection from monsters for at least 10 years. Unsure of what to do, she can only sit by as Akatsuki, who had overheard her conversation, goes to fight him. In the meantime, she is accompanied by Rieze, from whom she realizes that even after all this time, she really didn't now how Adventurers lived or thought.

Upon the death of both the ninja and Soujiro Seta, however, both Akatsuki and Rayneshia are berated for their naivete and unwillingness to work with others.

Rieze and Henrietta work together to come up with a strategy to defeat the rogue Guard, and Rayneshia is the one visiting Kinjyo this time, to ask him to turn off the magic circuit allowing for the operation of the Royal Guard. He repeats the downfalls of turning it off, all which she knew and was prepared for. Even though she was still afraid and wanted to just run away, she determines to herself that would go through with the plan. .

Homesteading the Noosphere arc
For her younger brother Icelus' eighth birthday party, Rayneshia travels from Akiba to Maihama, where Isaac and Charasin already were to train the Glass Greaves. Rieze accompanies her as a bodyguard, and indeed, some Westelande assassins appear to kill Icelus. However, Isaac, with his new danger-detecting earring, sensed the malintent of the Landers and challenged them to a fight.

Not long after defeating them, though, many Landers begin collapsing around them. Although Rayneshia and Icelus are not affected, their grandfather, Serjiad, was, and they gather beside him in worry. By the time he wakes up, they already moved him into a bed so that he could rest, and Rayneshia herself irately wonders where Krusty had disappeared to, vowing to find him and bring him back herself if she had to.

Log Horizon: People of the West Wind
Rayneshia makes a cameo in chapter 29, laying over a table as Elissa spreads a blanket over her.

Log Horizon: New Adventure Land
Rayneshia is a Super Rare recruitable character in the Log Horizon SNG. Instead of having a unique class, she is a Bard. She can be recruited by acquiring the SR premium summon weapon Princess' War Sword.

Trivia

 * Her middle name, El-Arte, may actually be a designation of her standing in the family, since the rest of her family also has -Arte in their middle names, but with different prefixes.