The 100 asked a lot of Clarke Griffin. Clarke became one of the biggest leaders in the series.
Each season slowly progressed Clarke's journey showing her transformation through each hurdle. It was not a quick and easy journey for Clarke, and she was tested numerous times throughout the series. Her people always came first, which meant sometimes Clarke's decision wasn't the most popular. As the series progressed, Clarke considered everyone to be important rather than just her own people. The question of how to save those she cared for while sparing as many innocent people as possible became an essential element in her plans.
The Delinquent Doctor
No one was ready for life on the ground. Not believing they would ever actually step foot on Earth, the delinquents were not prepared for what was to come. Clarke Griffin was not any more ready than the rest. However, she had an instant desire to see her fellow people survive, along with an understanding of medicine that came from her mother.
Clarke's medical background gave her urgency when the Delinquents were hurt, and her initial desire to find Mount Weather and later bring Jasper back became the initial reasons others began to look to her. Throughout the first season, Clarke and Bellamy became a team to keep the delinquents alive. But, it was Clarke's ability to do things Bellamy couldn't, such as mercy kill Atom, that gave Bellamy respect for Clarke and began hints to their teamwork.
Becoming A Leader
Although Clarke and Bellamy shared the leadership role at the Dropship, it became far more serious in the second season. After escaping Mount Weather, Clarke was put under the microscope, being Lexa's main communication to Skaikru.
While Bellamy was an Inside Man, Clarke was making alliances with the Grounders and working with Lexa to rescue the forty-seven. Clarke stepped up against Abby, making it clear that she was in charge. She holds a single-minded determination to rescue her friends that drives all of her choices, even those that cause the most pain.
Wanheda
In the final moments of season two, Clarke left Camp Jaha unable to handle her actions' guilt and grief. A time jump to a few months later reveals Clarke on her own, hair dyed red, as she survives alone. However, this doesn't last long into the season as she quickly and briefly reunites with Bellamy before being brought to Lexa.
As Wanheda, several are after Clarke for her power, and with a new identity comes the danger of others wishing to kill her. Season three finds Clarke standing beside Lexa, choosing to believe that Lexa is her best option to keeping Skaikru safe. However, by the season finale, Clarke is working with her friends again, determined to defeat A.L.I.E. Except, her interaction with A.L.I.E and Becca reveals one last horrifying piece of news.
Savior
Clarke spends a majority of season four trying to save the human race. All of Clarke's energy is devoted to searching for a solution that will allow Praimfaya to with survivors. Clarke is responsible for creating a list of 100 people to survive in the Ark if there is no alternative. She also spearheads the search for a Nightblood solution, sacrificing herself in the process.
In the end, Clarke makes a few significant mistakes concerning the Second Dawn Bunker and isn't even present when the door finally shuts. Instead, Clarke stays behind, working to ensure her friends' survival when they go to space. Unfortunately, Clarke was never certain if her sacrifice saved them until her reunion with Bellamy six years later.
Ally And Enemy
Six years alone with only one other person made Clarke very protective of Madi. The young Nightblood girl was all Clarke had, other than her radio calls to Bellamy, so Clarke was desperate to keep Madi alive. Clarke's major storyline throughout season five is making sure Madi is safe and providing her with a home. Amongst the war occurring, Clarke is more concerned with Madi keeping her home.
Clarke is against Madi becoming Commander, believing that is far too much responsibility for a child and not wanting Madi to deal with that title's negative parts. In all, Clarke spends plenty of time jumping between ally and enemy depending on how things are going before eventually choosing her friends over the Eligius crew.
Looking Inward
After her choices in season five, Clarke was on shaky ground with all her friends other than Bellamy. Clarke wants to move forward while also wishing her friends could understand how their actions affected her. But, of course, Clarke is left to bear most of the guilt, responsibility, and emotions toward her actions. Clarke tries to move forward with that in mind, referencing leaving Bellamy to die in Polis as her greatest regret.
However, most of Clarke's arc is about dealing with her past actions and how she feels about them. Clarke spends a lot of time in her mind because of Josephine's possession, which places Clarke's friends in unique positions of having to deal with her gone, at least temporarily. Meanwhile, Clarke's major hope for Sanctum is that they can follow Monty's advice and do better.
Grieving And Motivated
Even though Clarke is sidelined for most of season seven, it is still clear where her motivation comes from. Fresh off her mother's loss and with Bellamy, Octavia, and Echo all missing, Clarke has no interest in losing anyone else. Knowing she must follow them, Clarke, along with her friends, leave Sanctum behind for wherever the Anomaly brings them. Unfortunately, her goal doesn't work out exactly as she hoped.
In the end, Clarke believes she will be alone for the rest of her life as the only human not to transcend. But, after all the things Clarke had sacrificed for her friends, they do something amazing for her in return. Clarke's friends choose to remain on Earth with her knowing they will never transcend or have children. Clarke gets to spend the rest of her life in peace with her friends, having already owned her past actions but understanding that they were because of her love for her people.