In the early episodes of the show, Clarke told Monty that his mind would be the thing that saves them all. However, the way Monty does that was likely not how Clarke envisioned. Monty was one of the hundred juvenile delinquents sent to the ground. Monty was the primary genius before Raven landed, and then he and Raven were essential for finding answers instead of fighting wars.

RELATED: The 100: 5 Best Duos (And 5 We Don't See Enough Of)

Monty was crucial to the series, especially during his last two seasons. Many of Monty's most vital acts happen during the fourth and fifth seasons as he continually grew as a character. More often than not, Monty was doing something to help his friends survive, which allowed him several significant moments throughout the series.

Revived The Plants In The Bunker

With Wonkru prepared to go to war for Shadow Valley, Monty went to work for a way to remain living in the bunker. The hydro-farm may not have been working when Monty first saw it, but with the use of his algae, Monty brought the plants back to life and considered preparing the soil outside to use to farm.

Monty admitted to enjoying the algae during the six years in space to the extent that he was uncertain about going back to Earth. Unfortunately, Octavia's determination for Shadow Valley outweighed the significance of having a renewed food source in the bunker. Octavia burned Monty's hard work to ensure that Wonkru had no choice but to follow Octavia into war.

Revealed Clarke's List

Clarke Griffin using a radio on Earth to try to contact a spaceship in The 100 season 5

The back-up plan was to have one-hundred members of Skaikru survive in the Ark until the radiation from Praimfaya died down. Rather than inform the truth to everyone, only a select few knew about the list. That all changed when Jasper found in it while preparing a prank on Clarke. Jasper called out Clarke for playing God in choosing who gets to survive Praimfaya and who has to die.

RELATED: The 100: 10 People To Ship Clarke Griffin With (Other Than Bellamy Blake)

When Clarke uses the same excuses as Jaha had, "It's all for my people," Monty decides to make sure that everyone knows about Clarke's list. Gathering everyone's attention, Monty reads off the names of those who would be saved if the Ark were to be used as a shelter from the death wave.

Saved Octavia's Life

Monty Green in distress looking at something

Jaha brought trouble back to Arkadia with him after meeting ALIE in his search for the City of Light. Jaha's primary activity is to get as many people as possible to take the Key to join the City of Light. Unfortunately for Monty, his mother is one of the people who took the Key. Monty's mother is acting on ALIE's wishes, determined to prevent her destruction.

Monty's mother attacks Octavia during her time under ALIE's influence, and to save Octavia's life, Monty shoots his mother. Monty's actions had happened after telling Octavia that she belonged with the hundred after Octavia revealed that without Lincoln, she felt like she didn't belong anywhere.

Saved Murphy

John Murphy with his arms folded

During "Praimfaya," Murphy makes sure to come back for Monty after choosing the machine above him, something Monty approved of. After six years in space together, Monty and Murphy would have inevitably spent more time together, yet their interactions in the fifth season make it appear that they did not get much closer.

While several others have formed new bonds, Murphy and Monty still seem at odds, even if it wasn't to the same degree as it had been years prior. Yet, as a missile is about to hit Earth, destroying Shadow Valley with it, Monty doesn't hesitate to help Murphy get to the Eligius ship instead of leaving Murphy there to die.

Stayed With Jasper

Monty and Jasper in The 100

Monty and Jasper had grown up together and were best friends. While the two did not always agree in their Dropship days, the two still found time to reconcile. Jasper and Monty relied on each other after discovering Mount Weather was not the haven Jasper was hoping for. Their relationship took a hit after Maya's death in Mount Weather.

RELATED: The 100: 5 Characters That Will Likely Survive The Final Season (& 5 That Likely Won't)

Jasper spiraled in the aftermath of losing Maya and everyone who had helped the remainder of the hundred. Yet, it is the last moments of their friendship that proved how important they were to each other. As Jasper died, Monty stayed with him, holding him. A few years later, Monty and Harper named their son after Jasper.

Opening The Bunker

Jaha spent the fourth season trying to save people, as he was responsible for so much pain the previous season. Trying to find ways to have as many people survive as possible, Jaha found articles written about bunkers that people prepared for Apocalypse One.

Jaha's second attempt is more favorable than his first, but Jaha is unable to open it. It was Monty who figured out how to open the bunker by discovering how to find the key. Without Monty having joined the mission, it is uncertain if anyone else would have managed to understand the riddle.

Found The Viable Solution

To survive Praimfaya, there had to be an environment capable of handling massive amounts of radiation. As Clarke, Bellamy, and Raven try to determine how to find or deal with the situation, Monty realizes one space is right beneath their feet.

The Ark had orbited space for nearly a century being exposed to the vacuum of space and extensive radiation, enough that it could likely handle Praimfaya. After all the work Skaikru did to patch up the Ark to make it survivable, Ilian sets a fire that burns the Ark and makes it impossible for anyone to survive there during Praimfaya.

Found A New Habitable Environment

When everyone else went in cryo-sleep, Monty and Harper decided to enjoy the ten years on the ship without war. They lived together and eventually had Jordan Jasper Green, and were excited to wake up their friends once Earth was survivable again. Yet, that is not what happened. Ten years later, Earth was just as dead as the day they left and did not have anything to be desired.

RELATED: The 100: D&D Classes of the Main Characters

But, Monty did not give up. He spent years trying to crack the Eligius Three files and discovered that they had been searching for other habitable planets. Following their lead, Monty found a new place for his friends to live. Monty never got to see it, though, as it would have taken one-hundred and twenty-five years to reach the new world. While Monty could have placed himself in cryo-sleep, he said that he did not want to see it without Harper.

Was A Good Father

Jordan looks down at his hand in The 100

While there are hints of what type of father Monty was to Jordan, there is not much time anyone gets to see of Monty's time as a father. Other than holding Jordan as a baby, viewers are left to fill in the blanks of the types of parents Monty and Harper were based on the way they speak in videos to their friends and how Jordan speaks of them.

Monty and Harper had followed in Clarke's footsteps, telling Jordan stories of Clarke, Bellamy, and the rest of their friends as Jordan grew up. Unlike Madi, whose favorite was Octavia, Jordan's was Murphy. Toward the end, Monty and Harper asked Clarke and Bellamy to look after Jordan since they could not.

Left His Friends One Last Piece Of Advice

Similar to Jasper, Monty was tired of fighting and wished to live. Monty got that chance when he and Harper decided not to go to sleep, but to have a family instead and enjoy their lives. In the videos Monty and Harper made throughout the years, they updated their friends on what was happening.

In Monty's last video, he leaves his friends with one last wish as they look at their new home. Monty asks his friends to do better and show that Jasper was wrong about humans being the problem. Monty's friends take his words to heart and try to do better in Sanctum than they had on Earth.

NEXT: The 100: 5 Of The Best Parents On The Show (& 5 Of The Worst)