Lobster Johnson is a Hellboy pulp-era spin-off character. In that universe the Lobster battled underworld criminals, Nazi, and Imperial Japanese agents in 1930's New York City and even went to Europe during WW2 where he died (to reappear as a ghost in the Hellboy and BPRD comics).

He has a crew of helpers (for information, leg work, mechanical and engineering aid, and also battling mobs so that Lobster can concentrate on the main bad guys), a nosy reporter (Cindy Tynan, who develops a romance with one of Lobster's crew), a police force that doesn't appreciate his help and sometimes goes after "that vigilante".

Unlike more sanitized pulp heroes The Lobster believes in murdering the guilty, often killing with The Lobster's Claw, where his right palm both kills the victim and burns a claw mark on their forehead. The Lobster is also perhaps unkillable (except for that last adventure) in that he keeps getting into more and more dangerous situations (e.g. stuff falling on him or big explosions that destroy a room) where anybody would have died but he seems to come out badly wounded but still alive.

Sort of typical pulp stories and in general few references to the regular Hellboy universe. Some of the occult bad guys use Hyperborean speech and there might be one or two Cthulhu-type monsters. If you like 1930's pulp action then Lobster Johnson is for you.

I include the Crimson Lotus TPB set in the same era. It collects a five-issue limited series where a couple of Chinese agents are pitted against the Japanese Crimson Lotus during Japan's occupation of parts of China. The Crimson Lotus has witch powers and uses masked monkeys to do her bidding and she also lives on to appear in the main Hellboy timeline. I found the story less interesting than Lobster Johnson.