Batman: Last Knight on Earth #1
By Scott Snyder

Joker narrates having almost been with BM for his whole life, having adventures. As BM speaks with Alf in the Batmobile, through comp Joker continues on how BM's alarm is through his body scars, warning him. BM's tracking odd chalk marks around town, which disappear later, he putting together they made an outline of his figure, and his heart is placed in Crime Alley where his parents were killed. Then, BM sees a small body huddled under an umbrella on the sidewalk near a streetlamp, Alf warns him of the oddity, which BM recognizes.
Upon closer look, he sees the boy, 10 or so is deceased and as Alf warns him to move, the boy's arm clicks, and a bomb goes off. When he wakes, he's strapped to a bed, and a man with a wide smile assures it's over, Bruce slurring his words, and saying he's lying, but the doc denies this and says how the facility's happy he's back in reality, continuing of working there for 20 yrs in Arkham Asylum for as long as Bruce'd been there. Bruce denies this, and the doc lets him go vertical with the gurney and Alf comes in to say how no 1 blames him for what he'd done, killing his parents, this making Bruce go ape shit, again. Alf sharply has him see reason, and how his actions are hurting people, his fantasy of the doc being the Joker to his BM.
Alf leaves Bruce there, he wakes in a padded cell, and finds a T-Rex toy in the wall, shrieking he'd never believe them as he tears at the wall with his teeth. The next Alf comes, Bruce qs how he'd gotten certain skills, the librarian coaching him in different languages, and fighting from the doc at the gym. Alf then shows Bruce his cowl, which consisted of a janky bat mask, and straight jacket, Alf explaining the mask is from a shock therapy restraint. Next, Bruce is loose and assaulting orderlies left and right, the cops called, and also unable to stop him as he ascended the levels of the asylum.
When Alf confronts him, Bruce learns none of this is real, Gotham and buddies gone, Alf a hologram, but only to mask his older age, which makes Bruce wonder why he looked young, Bruce surfacing through sand, and uncovering Joker's head in a lantern, he waking, but not knowing how he got this way. BM agrees to take him along, despite his trying to make jokes. BM walks to the last stretch of Gotham to survive, no one alive, and even the green lanterns rings laying about, til the 1's attached to fingers and bodies, issue out big, sharp-toothed babies, hulk-smashing around, til something takes them out. Then, Bruce is pulled into an invisible ship by a black girl, and Poison Ivy driving, she clocking Bruce out with a tendril as they see he looks like the real BM.
When he wakes, he thinks he's seeing Amazons, Supergirl, and Wonder Woman among them, but the latter saying they only wore the costumes. She reveals he'd killed everything when he inquires. She tells him they're in Gemworld, where Diana'd created the chapel hall for the community, til it's destruction with Lex Luthor's televised message. The people rage by his preaching oligarchic tyranny, so BM's solution is to empower the people by letting them all in. This birth's Omega, who takes the East coast, and knows the anti-life equation (...humanity?), which controls all humans:

(Bender's wet dream). When Diana asks if he knew how he'd fallen, he shares how the 1st BM'd made a machine which cloned a BM every gen. Diana states she hadn't given the machine to Alf for another BM, but to give him Bruce. She also relates of Omega probably being native to Gotham, and is most likely a follower of BM, another shock to him. She then invites him to join them in the underworld, she making a deal for a realm with some light with Hades, for the 100k people they were able to save. She then leaves him to rest and decide whether he'd like to join them when they go. After chatting to a boy a who shouts an echo with him at Bruce's prompt, since it was against the rules. When Diana returns for his opinion on the plan, she sees he's gone with Joker's head.
Decent start. Hope it ends better like The Three Jokers.