Yeon Yihwa (연 이화, Yeon Yihwa; or "Yun Eehwa") is a D-rank Regular from the Yeon Family who has been climbing the Tower with Jyu Viole Grace and Team Tangsooyook after the very beginning of part 2. She was known by some as the "Yeon Family's Flare".
Currently, she was being held hostage somewhere by Yool and Kell, the two assassins from Zahard's Army who were tasked to kill Viole. Yool and Kell captured her because she will be exchanged as a bargaining chip to lure Viole into their trap.
Notes and Trivia
SIU has stated that her power level is unrivaled among the regulars (Viole not included). When referring to part 1, she'd be like Androssi.
She is very special because she came from a very rare family (the family word here might refer to her father's family blood regarding the special birth process of Yeon's family members).
She was very praised in the Yeon family because of the fact that the Yeon family's daughters are only born once every 100 years. SIU added that if she controlled her powers, she'd have an ability that will put Ran to shame.
The reason why Yihwa rarely has actions and screen time is due to SIU restricting her appearances because SIU suffered wrist pain from drawing flames.
She is slightly sexist, given the nature of her family.
Yihwa is a bad cook because she always ended up burnt the food. Her teammates often made fun and jokes out of it and prevented her from cooking.
Yihwa later learns how to make a barbecue without burning it. Her teammates have an open barbecue party every weekend to celebrate her accomplishment.. She then manages to cook vegetables, but still makes some mistakes.
She's the main comic relief for Part II; being conned and exploited wherever she goes.
One of her nicknames is "Hellion", traditionally a term used to describe a mischievous person, but is also attributed to those with a fiery, uncontrollable nature.
Her other nickname is "Yeon Family's Flare".
Rak identified her as "Angola Turtle", "Angolan Demon Lord/King", or simply "Angolan".
She still believes that Rak is a dinosaur.
She has failed the 20th Floor Test on more than one occasion.
She was the sole person at fault for causing Ja Wangnan to fail an attempt at the 20th Floor Test.
As it has been comically noted by many, it seems that Yihwa has begun to develop romantic feelings for Viole.
As shown here, whenever Yihwa and Viole are together, Yihwa starts out with tights, which have mysteriously vanished by the time Viole leaves.
She seems like a character roughly similar to Androssi Zahard (pretty, feminine, good stats). However, there is a degree of difference.
Yihwa and Viole is a slightly different type of pairing. Because Viole alone is just too full of melancholy, a character that acted like cooling medicine was created, and that character was Yihwa. Although she is strong, she is shaken up wherever she turns. That kind of concept.
Yihwa is a character that shows a bit more worried and conflicted aspect of herself. Her personality is a bit different from Khun Aguero Agnis who seeks to gain and use the power of the 10 Great Families. Of course, the greatest source of Yihwa's inner conflict is her natural tendency/character trait, Wangnan, and Baam (Viole).
(To Ja Wangnan) "I've got a bigger chest than you!! You stinking male ape!!"
(To Prince) "I'm sorry for saying something like this, but both of you should learn to start pulling your own weight."
(To Prince) "Is there even any point in looking? The score of someone who borrows the strength of others to climb..."
(To Viole) "Wait!! What do you mean?! Nobody can be your teammate?! Aren't you full of yourself?! Oh yeah!! The big gangster with the symbol of the FUG!! How can you eliminate people who might pass with you?! How can you be proud with that fake symbol!! You should be embarrassed!!"
(To Hon Akraptor) "Then... what are you going to do? Are you going to laugh at me too? For being an idiot who can't even control her own powers? That I'm a defective product?"
(To Viole) "Am I your teammate?! Don't lie!! You fooled your 'Teammates' by coming here secretly to meet with the FUG!! What are you planning with them, huh?? You trick us like this and you call us teammates?! It's not funny!! You are worst than dirt!!"
(To Goseng and Miseng) "I made up my mind! To be a real elite of the Great Family!! I will bear witness to all the dark sides of the 10 Great Families as I go up the Tower with Viole!! Then after I become a Ranker, I will go back to my family and correct their mistakes!! To show my will. I will re-take the cooking duties Mr. Viole did for me. A real elite should know how to cook for oneself! I will be the cook starting today!!"
(Discussing Viole's happiness with Akraptor) "I didn't know he could make such an expression..."
(To Beta while fighting him) "You are trying to make others feel the same as you did. You are really selfish and nasty! Don't you underestimate us!"
(Thinking about Wangnan to herself) "The ring that guy had. It definitely had the crest of Zahard carved on it. I didn't think he would be someone who would hide something from his teammates. But, why would he do that? What would he be hiding from us?"
(To Hwa Ryun) "Shut up! I have only accepted you cause I had no other choice, but I don't need help from a FUG criminal!!"
(Thinking about Wangnan and Viole to herself) "That monkey guy is a mistake made by the 10 Great Families and Zahard? Does that mean he is someone to remain in the shadow, unseen. Like a baby Zygaena? Then, if I keep on going this journey. Eventually, I will face my family's blunder. But, I have no choice. I will ride that damn Hell Train or whatever. Cause I decided to follow this guy till the end."
(To Angel) "You guys are nothing but cancer to this Tower!!" 
(To Hong Danhwa) "You don't have to worry just because I'm from one of the Ten Families. Because I think that facing the truth properly is the right thing to do."
(To Khun Aguero Agnis) "I'm definitely going to get on the train!! Even if I have to put my life on the line!! I will!!"
(To Viole when she fell accidentally at the Name Hunt Station) "It's okay. It's definitely fine."