So, in 10th Member, who are my characters?
Who are they?

1. SANA

Sana is a clingy and expressive girl. Clingy because she just can't be alone. She likes to be with someone, even doing physically with them, like hugging, kissing, holding hands, etc. She is a simple girl and only one simple goal: Not to be alone. She loves helping people, as much as she needs to be taken care of by the others. She's mostly clueless about the situation (and acknowledges that). I think sometimes that makes her a little bit unconfident because she's not the brightest member in the group. The pabo one. Dumb and helpless. What she's afraid the most is when she depends on someone too much.
Sana can easily express herself. She laughs so loud and smiles so bright when she's happy. She screams when she's afraid or shocked by something. She's mad when there's something that she doesn't like. This is why at the first time she met Haeju, Sana was the only member who was mad at Haeju. She shows her feelings easily. At that time, Haeju appeared as a quiet, arrogant, and serious new member and Sana was afraid that Haeju's attitude would affect Twice's joys and friendliness. Haeju used to be a treat for her. But now she's so clingy to Haeju because the latter doesn't fight Sana back when she's "too close" with Haeju. Lowkey, Haeju likes those physical touches tho, kekeke...
As I already said, Sana only has one wish: Not to be alone. As long as there's at least one person besides her, she will feel safe and happy. Usually, the method she uses is to be clingy itself. She loves to radiant with whoever around her. She'd love to help everyone because she likes giving an impact on that person.

2. TZUYU

Tzuyu is loyal and expressionless. This how she 'becomes' after the appearance of Haeju to the group. Tzuyu is the maknae of the group and she used to always adapt to her unnies. Tzuyu almost doesn't have personality. She's loyal to the members by giving them what they want. On the outside, Tzuyu appears as a savage an ignorant person because she just doesn't like to show how much she cares to the members. That's just how she likes to present herself.
After Haeju joined, for the first time there's a member who always follows her. Haeju was new so she thought Tzuyu was "harmless" to be close with, so Haeju was so opened to Tzuyu compared to the other members. That was why the latter was so amazed tho. She felt respected and appreciated by Haeju. Usually, she was the one who 'follows' people but Haeju trusted Tzuyu as her guide to getting to know Twice. 
Since then, every time Haeju needs something Tzuyu's willing to do anything to help her. She wants to be useful to her unnie. Being loyal is just how she thinks is the best thing to do as a person. 
Tzuyu is not someone who forces someone to do anything but instead, she gives people what they really want. When Haeju needs to rant out or even curse, Tzuyu listens to her instead of telling her not to be angry or to behave better. Tzuyu is not a decision maker nor a problem solver. She just likes to say what people want to hear.

3. NAYEON

Nayeon is arrogant and witty. Although Haeju is the oldest member and Jihyo is the leader, everyone looks up at Nayeon the most. She's confident that she's brave to talk with anyone from any group ages. She's dare to try anything new and interact with variants of people. That makes her knows how to deal with a lot of things. Nayeon isn't shy so people love to talk to her, heck Nayeon usually talks to that person first. That makes everybody loves and admires her. Nayeon is not just the center of Twice, she's easily the center of the universe around her.
For Haeju who has a poor social skill, Nayeon is just too good for her. Too perfect. That's why Haeju interprets Nayeon's braveness as being arrogant. Nayeon indeed not slow when it comes to taking action. She's on fire. But that doesn't mean Nayeon doesn't care with people around her. Of course Nayeon cares with Haeju, but for Nayeon, Haeju's too-sensitive feeling is too slow and complicated for her.
Nayeon's biggest motivation is to experience various things. She loves to do anything quickly, joking without thinking but then forgive people right away. That way she can move on to the next thing she can experience, like 'What next after this? What next?'. Nayeon is not a detailed person, unlike Haeju. That's why there is always a tension between both of them.
 

(to be continued)