He refused to hold a grudge against
What shook him up so much wasn't Uri's power, but Uri's kindness. Uri could've easily killed him, but instead bowed down and apologized for the government's treatment of the Ackermann family. In doing so, Uri completely upended Kenny's worldview.
In the 進撃の巨人 ANSWERS/Shingeki no Kyojin ANSWERS Guidebook, Hajime Isayama, the writer of the series, states that Kenny was attracted to Uri.
Personality. Kenny's main goal was to obtain power, and his personality was molded around this goal. As such, he was a ruthless, sarcastic and manipulative individual who did not hesitate to do anything to get the job done, including a murderer or a traitor.
At the brink of death, Kenny confesses that he is Levi's uncle, explaining that he left Levi because Kenny viewed himself not fit to be a father.
Since he uses the term "branch" it's likely not his immediate family (parents and siblings). I figure they're probably cousins, perhaps distant ones, since he doesn't bother with names. Kenny also mentions his sister's name, Kuchel, so definitely not Mikasa.
He's Mikasa's uncle by her mother. "Attack on Titan" creator Hajime Isayama doesn't reveal Levi's age but he did say Levi is “surprisingly old.” Also, Mikasa's father was tall and blonde—nothing like Levi.
Obviously, that doesn't mean that Kenny didn't care for Levi at all, but we can assume that he didn't care that much. Kenny didn't want family nor did he care for the Ackerman clan and their grudge against the King. He did want to find his little sister, but that's it.
7/10 Kenny Ackerman
Kenny is Levi's uncle and is preceded by his notorious reputation. He was an infamous serial killer, who would brutally murder people without a second thought. Kenny had no qualms about killing people, and he continued to do so until he met Uri Reiss.
As it turns out, Levi's mother was Kenny's sister, who died when Levi was very young. As his only living family member, Kenny felt he owed it to his sister to look after her son, his nephew. Once Levi was able to fend for himself, Kenny felt he had fulfilled his obligation to his sister and left him.
He wanted to know what does it feel like to be kind and compassionate. His grand dream was to take the Founding Titan and see the world like Uri once did.
As a result, the hackers blackmail him into committing various crimes, including murder. While it is initially assumed that Kenny hasn't done anything wrong, as he was only caught masturbating to internet pornography, the ending reveals that he was looking at child pornography.
So according to the man himself, Levi did feel sadness and a sense of loss at the death of Kenny. Learning Kenny's identity, that he was his uncle and not his father, gave Levi relief.
Kenny hides behind the couch because he's waiting to see if the magic powers will work to make him feel better, too. Momma starts making Kenny do stuff with Rufus, but Kenny doesn't feel like playing with toys anymore, so he gives all his dinosaurs away. She also makes Kenny do stuff with Byron and Joey.
But Kenny ignores all the warnings and gets in the water. He starts trying to catch some of the fish hanging around in the shallow water. Then he notices a turtle out in the deeper water. He takes a few more steps out and makes a grab for it.
Kenny tells Byron that Larry stole his gloves, and Byron takes Kenny to find Larry.
Attack on Titan is still Eren's saga. While he seems to be losing sight of his friends, one can't discredit Eren's past actions, which are very much heroic. After all, he's the one who defeated and captured Annie and became instrumental in revealing Reiner and Bertholt's plans.
As a result of his parents' teenage Cthulhu-worshipping ways, Kenny is cursed to be an immortal abomination. Every time he is killed, his mother births a new baby Kenny who then ages rapidly to his 8-year-old form, ready for his next adventure.
Zeke Yeager, otherwise known as the Beast Titan or just The Beast, is the main antagonist of the Attack on Titan series. He is the son of Grisha Yeager and Dina Fritz, who had him join the Marleyan military for their own agenda.
Uri Reiss (ウーリ・レイス Ūri Reisu?) was the younger brother of Rod Reiss and the uncle of Historia Reiss. He was the true king of the Walls for some time until the year 842 and was Kenny Ackerman's best friend. He inherited the Founding Titan from his father, and passed it along with the crown to his niece, Frieda Reiss.
⁵ Introduced in Year 854. ⁶ In the Year 829, Kenny was a young man (and serial killer), so it can be assumed that he was around 20 at this point.
She raised him alone in the brothel for some years, until she got sick and died when Levi was just a little boy. She seemed to be a loving mother to him, as Levi was visibly affected when she died.
Mikasa sits under the tree where the two played as children. She mentions that Jean might ask her to marry her and that she hasn't made up her mind. While the majority of the community believes that she would go on to marry Jean, she still loves Eren and will continue to do so till her last breath.
In Attack on Titan ANSWERS, Hajime Isayama stated that "[Mikasa, Levi, and Kenny] are all part of the same Ackerman bloodline.
A few episodes before that he is actually surprised Kenny's last name is Ackermann. But after doing some digging i found out that in the Manga during the cart scene Levi also mentions he is an Ackermann.