If you cannot wait for the next season and want to know what happens next, I’ll suggest you start reading the manga from Chapter 39 after the Katana Man Arc.
Everyone’s all trained up and ready to go. It’s the second to last episode and its the newly formed Division 4 versus Katana Man and all of his Yakuza Cohorts.
In the aftermath of the Katana Man attack, the Public Safety Division mourns and reshuffles. Everyone must pursue new strength if they’re to survive.
Himeno is gone and most of the public safety bureau is dead, but with a final act, Himeno uses the Ghost Devil to unleash the fury of Chainsaw Man.
The aftermath of Eternity Devil death celebrations takes an uncomfortable turn, But there is no rest and relaxation for the agents of the Public Safety Bureau.
The battle with the Eternity Devil comes to an end and it’s time for Himeno to keep her promise to Denji. But not really since alcohol is involved.