Gunshots and Gunpowder is the second original chapter in Attack on Titan Reborn.
Plot
Axel realises that he's going to die, so he runs and kills Rooster and Daley. He then climbs over the wall and gets fought by some Survey Corp members. Axel transforms back into his human form, only to be attacked by the same Survey Corp members. He is then taken into custody and put in a cell, which is when he kills himself.
Summary
After Rooster and Daley leave Axel on a tree branch to get a rifle, Axel thinks about his options. He decides to transform and run. Axel bites his hand and transforms into the Morphing titan. He spots Rooster and Daley riding their horses a few miles away. He kills both of them. Axel continues to the wall, which he climbs. When sitting on top, he watches Bertolt's death. He then climbs down the wall. Scouts attack him when he approaches Armin. Axel ignites his titan, burning some of them. Then, he transforms into his human self. His titan's burning body falls down. The same Scouts slice Axel's nape. Axel falls down in shock. He starts bleeding out. The Scout goes over to finish him when one realises Rooster and Daley never made it back. Axel starts laughing and grinning his head off.
The Scouts take Axel into custody for some unknown reason. Axel asks where Erwin is, and Hange tells him what happened. Axel is upset by the news. Hange then starts questioning him about why he betrayed everyone. Axel tells Hange the truth. Hange says that she has no choice but to execute him or take away his titan-shifting abilities. Axel replies by saying he's going to die anyway. Hange nods and leaves. Axel takes the gun he had hidden down his pants. He cocks it and ends himself.