Pre series: Tsukuyomi is the youngest of two siblings who are descendants of a line of royalty who can control time. As she is deemed to be the more powerful of the two, she was appointed to be the next in line for the throne. Her older brother grew jealous of this and erases her memory and throws her into another time line where she is picked up by the resistance. She grows up with them and eventually joins the fight against the Demon King.

* The series starts with Tsukuyomi and Geiz in their current present timeline in 2068 (the future of the series) where her comrades in the resistance are killed by the demon king. She survives the battle after being thrown into a rift by her comrade. (Episode 1)
* Tsukuyomi travels back to 2018 with Geiz to find Sougo and shows him what his future is like in 50 years where he turns into the demon king. While Geiz has arrived to kill Sougo to prevent the future from happening, she has a different idea and decides that he is worth saving as he has the ability to change his own future. She rescues Sougo from Geiz's attack and takes him back in time in order to explain to him about how he comes about his future and how his watch works re attaining power and becoming king. (Episode 1)
* Tsukuyomi and Geiz move in to live with Sougo. Then follow him around in his daily life to try and determine whether he will turn into a demon king. (Episode 2 & 3).
* Tsukuyomi continues boarding with Sougo even though Geiz has moved out because she wants to see things with her own eyes. (Episode 10)
* She yells at Sougo for playing with time and even meeting his own self from the near (3 days) future. This isn't a major plot for the timeline but something cute that happens. Also the episode where she slams Sougo down onto a table to demand information. (Episode 11). Geiz moves back into their shared residence.
* Time is sped up and they realize that the end of the peaceful times might be sooner rather than later. (Episode 15). With the help of Decade, Tsukuyomi is able to show Sougo her future and the destruction he brings. She meets the Demon King with Sougo where she finds out about his childhood dream. 
* Tsukuyomi watches Sougo give up his power but she feels a bit of disappointment when she walks away from him to go back to their own future. She then notices that the enemy are still after a now powerless Sougo and asks Geiz to delay their plans to help him. (Episode 16).  Sougo regains his power and Tsukuyomi doubles down on her resolve to help him become a kind demon king.
* With the appearance of white Woz, Tsukuyomi starts to have doubts about Sougo. She watches him getting stronger and stronger and panics that he may suddenly go out of their reach so she joins forces with White Woz and they move out of the residence into their own to stay separated from Sougo. During this arc, Tsukuyomi is constantly questioning whether Sougo is trustworthy and whether they can really change the future. (Episode 18  - 22)
* Tsukuyomi helps Geiz upgrade his system to Geiz Revive. However, during the time she's away from Sougo and helping Geiz, she's intrigued by Sougo's past and why he became the way he is. She starts investigating by first speaking to his Uncle and then travelling to the past to see what happened with Sougo's accident with her own two eyes. This is when she first realizes that Swartz is more involved with everything than they realized. While saving child Sougo, she unintentionally helps Geiz reach his final Geiz Revive form. It was all a mistake as it appeared to Geiz she was trying to kill Sougo when instead she was trying to shoot past him to save him from Swartz. (Episode 25 - 28) Tsukuyomi barely manages to survive with the help of Decade and comes back to the present time to convince the two to stop fighting only to realize they have already made up and everybody moves back in to the residence.
* It's finally revealed that when Tsukuyomi joined the resistance she had lost all of her memory. This is also when her powers start to surface and she freezes time by accident while she was is to be attacked. (Episode 31). This catches the attention of the time jackers who start to question who she really is. Woz directly questions her about her abilities but this just causes confusion as she didn't intentionally stop time.

Tsukuyomi is a confident person (for the most part) and always does what she believes is for the best of everyone. When she believes she's doing the right thing, she won't waver from her course of action. The one big thing that does trip her up is her own self confidence when it comes to her past. As she has amnesia for about three quarters of the series, she puts everything into her being as a resistance fighter going against the future where Sougo becomes the demon king and destroys everything. This confidence gets knocked when she realizes her very own past puts her into the enemy's camp.

In the first episode, although she apologizes for her actions right before following through, Tsukuyomi mimics Sougo's voice and pushes him right into the middle of conflict. In this one scene she's showing her confidence of following through the course of action she thinks is right (she needs to prove that he really is the demon king that she is looking for) but she also shows compassion where she asks if he's okay. This compassion becomes one of the biggest core parts of her personality. It comes through with the fact that even though in her own timeline Sougo is the great demon king that killed almost all of her comrades, she rescues him from the one person that she knows from the future because she believes he can be a kind hearted person.

This actually happens twice in the series. Later on in the series, all of their memories (except Sougo's as he was in another time line) were wiped. Geiz goes back to trying to kill Sougo and even though Tsukuyomi only knows him as the killer demon king, she once again saves Sougo from being killed by Geiz and gives him a chance to explain himself. She is able to put aside her own rage to understand the other person. 

This compassion works against her at the end of the series when she realizes that to really save their future, she must kill her own brother as he's trying to manipulate time for his own ends. She's unable to follow through killing him in her past even if it is the one big thing that would be able to change all of the bad things that happen.

There are two other parts of her personality that can override this sense of compassion. The first would be how easily she can give in to her fear about the future. As she's from the future, she places a lot of confidence in knowing how things will go. When she notices that Sougo is rapidly gaining the abilities to turn into the demon king and that the future as she knows it is being replaced by a new one, Tsukuyomi switches sides and works with White Woz instead of Black Woz. That is, she suddenly starts pushing Geiz towards gaining the ability to defeat Sougo. She never outright says that she would like Sougo defeated and it's not explicitly mentioned in the show but I believe that even though she is pushing Geiz towards leveling up, she doesn't actually want Sougo to be killed. She just wanted to make sure he was able to stand up to Sougo if anything did happen. 

When she goes through with her own investigation into Sougo's past and realizes the truth behind his desire to be king, the fear is quickly removed. Once the fear is removed, she quickly goes back to Sougo's side and regains full trust in him once more. In this sense, she will do what's right, even though she still has feelings towards Sougo (as a good friend), she will shut down her own feelings and back up Geiz to fight Sougo to save everyone's future.

The second is her logic and applying that logic to doing what she believes is the right thing for the best outcome. At the end of the series when she realizes that there is no other way to save the world. Tsukuyomi "betrays" all of the comrades that she has stood side by side with and joins forces with her brother once he has made all of his intentions clear. She hides the conflict by looking away from him when she swears her allegiance and quietly waits by his side, biting her tongue whenever he talks to her about her loyalty. She manages to stay on course and continue doing what is right by allowing her friends to fall in the final great battle and then stabbing her brother in the back as this was the only way to win. 

Tsukuyomi has full belief in her moral compass and will do what she believes is the right thing for the world firstly and then her friends. As above, she will place her friend's lives as well as her own at risk for the greater good. But this takes a beating when she realizes she has the ability to stop time and this places her in the same realm as the very people she is trying to fight against. It takes talking to a number of people to realize that it doesn't matter what her past is or who she was, as long as she holds onto her own sense of self, as the only thing that matters is who she is right now. It only takes just over an episode for her to regain her footing after this revelation. It's a testament that she is a strong character and can hold her own. As soon as she accepts herself and that her past doesn't make her a bad person, she immediately starts using her time freezing powers for good (saving people from falling meteors). 

Outside of all of the serious information about wars, demon kings, killing siblings and the shock of regaining her memories, Tsukuyomi is actually quite a happy person. She enjoys spending time with her comrades and eating the food prepared by Sougo's uncle where they all reside together. She enjoys eating spicy food but still can't resist the tasty sweets that his uncle makes for them once in a while. She is also quite devious and enjoys assisting Woz and Sougo to pull pranks on Geiz. Unlike the other three, Tsukuyomi isn't afraid of ghosts and does a great impersonation of Sadako with her long very straight black hair. She may seem like a serious person when you first meet her as she doesn't smile much but once she lets down her guard she is very loyal and a fun person to be around.

While she is a very polite person around people that she has just met, once you get to know her a bit more, other little nuances of her personality show through. She gets aggravated quite easily and has a slightly short temper. She more often than not will yell at the other guys that she lives with to quiet down so they don't destroy the residence. She is also not above yelling at people when she thinks they're doing the wrong thing (Sougo meeting with himself and potentially breaking time) and throwing them against things to get information out of them (slamming Sougo down on a table when he was hiding something). If she's in a hurry she will shoot first and ask questions later (her gun stuns not kills so it's okay...really.) Above all, even though she does feel frustrated and angry quite often, she will do her best to accept the people around her and help them be the best they can be. Even if she does roll her eyes and sigh at them a lot. 

* Temporal Freezing - As a descendant of a royal family with time control abilities, Alpina has the power to freeze time at will.
* Power absorption - Alpina is able to absorb time manipulation powers from another person. 
* Energy Blade - Alpina is able to create a white energy blade with her hand for offensive purposes.
* Fire arms - Adept at using fire arms 
* Basic fighting abilities - Mainly for self defense unless she is transformed into Kamen Rider Tsukuyomi
* Mechanical knowledge - She is often tasked to fix their "Time Mazine" when it's damaged in battle. It's basic knowledge, she spends a lot of the time angrily growling at it. She is adept at controlling the machine to travel through time and battle.
* Research - She is adept at researching information required for their battles. Alpina uses a small tablet sized device to look up information to help her in this. Often she will head out on her own to further her research in person.