Charlotte is an anime original series created by Aniplex and P.A. Works that ran for one 13-episode season. Despite a strong premise and captivating characters that drew in many fans, a Season 2 is unlikely -- which is a shame. While an anime original doesn't have source material to pull from, there are many plot points that left Charlotte with strong potential to keep moving forward.
In the anime, a comet named "Charlotte" passes by the earth every 75 years and spreads dust that causes children to develop special abilities after hitting puberty. While these abilities are lost as adults. having one is dangerous because of the many people looking to exploit their power. So ability users protect each other by attending a special school for hiding kids with abilities. One boy, Yu, has a unique power that could save everyone -- he can plunder anyone else's ability and take it for his own.
Charlotte Should've Expanded Yu's World Travels
The final episode of Charlotte acts as an entire season being summarized and glossed over by plot convenience and rushed pacing. As the only person capable of plundering abilities, Yu travels the world to plunder all abilities on earth so he can prevent others from being exploited. This journey would take years, but Yu starts and accomplishes this goal all in one episode.
At the start of his journey, Yu conveniently finds and plunders the ability of someone who can locate other ability wielders instantly by looking at a map. Soon after, he obtains the power to know every language in the world and to never need sleep. Charlotte's plot conveniences give Yu everything he needs to fulfill his mission without the typical difficulties you'd expect from such a large-scale global quest. Meanwhile, he occasionally runs into people who don't want their abilities plundered and they fight back, but Yu is nearly invincible and completes his tasks with little to no difficulty.
As he travels around the world and is faced with ability wielders of all types, this journey could've made a captivating Season 2 by itself. Had the plot conveniences been avoided, viewers could've witnessed Yu's personal growth as he's forced to adapt and persevere through his monumental mission and responsibility. Not only would he have major obstacles to climb, but he was bound to meet all types of people and ability users around the world, giving Charlotte major potential to have new and more developed characters.
Nao & Yu's Relationship Development Needed a Season 2
Nao and Yu's long-anticipated relationship is just beginning to blossom when Yu must leave for his mission around the world. She aids him by giving him a cheat sheet of things to say and do on his mission, which proves helpful to Yu on many occasions. As he absorbs countless abilities into his own body, his mind gradually descends into madness because he can't physically or mentally handle the sheer amount of powers he obtains.
Yu loses his more of his mind with each plunder, becoming maniacal and relishing in his known nickname: the "One-Eyed Grim Reaper." At one point, he questions why he's doing the mission in the first place and considers taking over the world, instead, with his god-like powers. As Yu's mind is overwhelmed and he gradually forgets all of his memories, Nao's notecards preserve his one shred of sanity. Even though he doesn't remember who made the cards for him, his heart can still recall that a girl special to him made them and they bring him back whenever he falls too deep.
While Yu's descent into madness would've made a compelling enough premise for a Season 2, it's hard not to imagine how Charlotte would've played out if Nao had gone with him and their new relationship had a chance to develop. At the end of the finale, Yu nearly dies after he plummets the last ability on earth and is returned home to the hospital. He wakes up next to Nao but doesn't remember her despite their agreement to be lovers. A Season 2 could've given viewers the opportunity to see Yu gradually remember Nao as they made new memories, giving a better sense of closure to Charlotte.