Reiner was an early antagonist and supporting character of the Attack On Titan series. He used the Armored Titan to crush Paradis' walls and facilitate the Warriors' efforts to steal the Founding titan for Marley. After revealing himself, he was nearly even successful.
Despite his original status as a villain, Reiner has engaged in dozens of heroic actions that added depth to his character and made him well-rounded. By identifying the times he was a good person, we can better appreciate how divided his personality was and the ways he actually helped the Eldians he claimed to loathe.
Warning! Manga spoilers ahead!
10 Reiner Helped Eren Train With His ODM Gear
At first, Eren performed poorly at Shadis' training camp. He was unable to master his ODM gear since the proctor had deliberately rigged it in order to discourage him from joining the Scouts.
In the middle of the night, Reiner and Bertholdt both agreed to give him a hand with balance despite no personal benefit of their own. This illustrated the warrior's humanity, given the fact that he did not yet know Eren was the Attack (and Founding) Titan.
9 Reiner Helped Eren Practice Hand-To-Hand Combat
One of Shadis' drills was a test of hand-to-hand combat. During this period, Reiner and Eren sparred together in addition to observing the cadets around them.
Reiner also arranged for Eren's direct duel with Annie Leonhart. Although he didn't realize it at the time, doing so would familiarize the young cadet with her martial arts and enable his victory in many battles to come. Moreover, it helped to identify the Female Titan, given that it fought identically to the way Annie did. Should Reiner have kept quiet, Eren would have missed out on two important lessons.
8 Reiner Saved Everyone From A Pure Titan At Utgard Castle
During the siege of Utgard Castle, a pure titan managed to breach the defenses and infiltrate the tower. Since the space was far too confined to use ODM gear, Reiner charged forward, taking the monster on his back and throwing it from the ledge of the building.
Not only was this a display of enormous strength, but it also epitomized what he was willing to sacrifice in the name of his fake comrades. Should he have simply remained in the back of the formation, the Scouts likely would've suffered significant casualties.
7 Reiner Came Clean About The Warriors' Identity To Eren
It was an extremely difficult process to incriminate Annie Leonhart as the Female Titan, one that the Scouts admitted was based on a guess. Considering that Reiner and Bertholdt were much more subtle about their intentions, it would have been nearly impossible to collect sufficient evidence to expose them.
Fortunately, the heroes didn't need to. Overwhelmed by the stress and trauma of being a Scout, Reiner came clean about his desire to collect Eren and began a reckoning that was long overdue. Should he have kept the secret, Bertholdt's Colossal would have had many more opportunities to crush the walls.
6 Reiner Fought Zeke In An Attempt To Save Annie
When Zeke finally decided that it was time to move against Paradis, Reiner fought him for the right to save Annie first. He didn't want to leave her behind, both since she possessed the Female Titan and due to the fact that she was a close comrade.
Unfortunately, Zeke defeated him soundly in an off-screen battle. As a result, both Reiner and Bertholdt were obliged to follow his plan preceding the second battle for Shiganshina.
5 Reiner Gave Falco Advice About Becoming A Warrior
When Falco shared his concerns about Gabi's ambitions concerning the Warrior program, Reiner displayed a genuine interest and listened closely. Although he admonished the child for suggesting that there might be a flaw in the Marleyan state, he also told him that the only way to protect his friend is by surpassing her and becoming an even more qualified Warrior candidate.
This was advice Falco took to heart, and he quickly began to match Gabi in the field. Ultimately, he would become a titan shifter - albeit under more different circumstances than any could have possibly anticipated.
4 Reiner Became A Warrior For The Sake Of His Family
In addition to avoiding (most) of the persecution Eldians faced, Reiner had another reason for aspiring to join the Warriors. He wanted to provide a safe and happy life for the rest of his family, even if it meant facing insurmountable danger.
Reiner's mother, Karina Braun, was even more indoctrinated than he was, and the actions her son took for the sake of the country made her proud. She only regretted forcing it on him during the Rumbling, where it seemed as if no one would survive.
3 Reiner Tried To Save His Home From Eren's Massacre
During Eren's attack on Marley, it seemed as if no one could stop him. Annie and Bertholdt were already defeated in the prior failed mission, and neither Lara nor Porco managed to last longer than a few minutes. Even Zeke was defeated swiftly and decisively by Levi (even though he took a dive).
Gabi and Falco both cried Reiner's name, providing him the energy he needed to rejoin the fight and confront his nemesis. Although failing to defeat Eren, Reiner managed to save Porco and deny Eren the Jaw titan's power.
2 Reiner Put Aside His Prejudices & Worked With The Eldians To Stop The Rumbling
One of Reiner's most difficult (and heroic) actions was putting aside his differences with the Eldians to defeat Eren. This not only entailed judgment for his previous sins (such as murdering Marco), it also meant he had to forgive Armin for his role in the death of Bertholdt.
Regardless, he made a fantastic teammate once both factions had aired their grievances. Reiner was particularly useful during the attack on the Yeagerists' base, where his Armored Titan provided a perfect distraction.
1 Reiner Subdued The Source Of All Living Matter
The Source of All Living Matter was a mysterious, worm-like appendage that connected Eren with the Rumbling. After Pieck's explosives severed his head, the creature was dislodged as well.
Realizing what was at stake if the Source was able to reconnect with its host, Reiner seized and began to wrestle with it. He even managed to pin it down while being viciously attacked by pure titans - specifically, giants who were once his close personal friends, Jean, Gabi, and Connie.