You might want to check out 'Jormungand'. It has a similar tone of violence and adventure, and features characters operating in a dangerous underworld. The plot developments and action sequences are comparable to Black Lagoon.
One such manga could be 'Gangsta'. It shares elements of crime and action like Black Lagoon, with complex characters and gritty storylines.
Another option could be 'Vinland Saga'. While it's not exactly the same genre, it has intense drama and well-developed characters, similar to the appeal of Black Lagoon. It offers a unique take on historical settings and conflicts.
The best chapter pointer here is Chapter 51, "The Great Lodging Competition". It opens with Oh, okay." After uttering two syllables indifferently, Jiang Li bent down... and closes on If I opened a bar here, wouldn't I become a savior?" Jiang Yan was....
Look to Chapter 57 for the clearest answer. It begins with Lu Xingchao's numerous fans were stunned., keeps building through Holy shit, what's up with God L?, and lands on I'm saying, big bro, can you at least reply to me?.
Look to Chapter 54 for the clearest answer. It begins with Five minutes later, the people of Chixia Village, who had received the..., keeps building through Leading them was the village chief himself., and lands on She was also polite and friendly, and to top it off, she was good-looking,....
Chapter 8 is the strongest chapter-level answer because it starts from The resentment that had barely calmed among the crowd surged back two... and follows through on Other people with a handsome and charming appearance often try to conceal....
A practical answer is Chapter 46, because it turns the idea into a concrete scene. The chapter opens with Upon hearing this, everyone but Jiang Li perked up with high alert., adds pressure through There must be some mistake with the crew's calculation, I demand a..., and ends on Did you calculate.
If you want the clearest chapter reference, go to Chapter 53. Early on, Night had fallen over Chixia Village, eerily void of any human sounds.; later, the chapter leans on Jiang Li followed the village chief's wife down a narrow path leading to....
Look to Chapter 56 for the clearest answer. It begins with Lei Shen originally had no idea about the trending topics on Weibo., keeps building through He had been busy renovating his studio for a while and hadn't even had..., and lands on At this moment, Lu Xingchao was still in the dark..
A practical answer is Chapter 23, because it turns the idea into a concrete scene. The chapter opens with Although Jiang Li exerted very little strength, Jiang Yan instantly felt..., adds pressure through So the moment the news broke that Jiang Li was entangling with Shang..., and ends on However.
If you want the clearest chapter reference, go to Chapter 61. Early on, Hahahaha, oh my god, Jiang Li's mouth is even more venomous.; later, the chapter leans on She broke Jiang Yan's defense with just one sentence." "Laughing to death,....