kill
Explanation
The Joke
A medieval-looking warrior announces "I'm gonna kill someone on the road today!" as he gets into his car, setting up the expectation that he's about to commit murder. In the next panels, he declares he's "ready to kill" and that "here we are, prepared to be hardboiled road-ragers." Then from "Heck's Heart" he starts to say "I start it... oh oh no!" as he notices a "Baby on Board" sign on the car ahead. In the final panel, he says "Boy I'm glad I saw that first!" -- implying the sign actually worked to prevent his road rage.
The comic plays on the common joke about "Baby on Board" car signs. Many people are cynical about these signs, questioning what exactly they're supposed to accomplish -- are other drivers supposedly going to be more careful just because there's a baby present? The comic takes this to an absurd extreme by presenting a genuinely murderous road-rager who is completely dissuaded from violence solely because of the sign, as if it were a magical ward.
The Humor
The humor works on multiple levels. First, there's the visual absurdity of a medieval warrior driving a modern car. But the core joke is the satirical commentary on "Baby on Board" signs -- by showing the one scenario where the sign would actually be useful (deterring a literal would-be killer), the comic highlights how pointless they are in everyday situations. The implication is that if you need a sign to tell people not to crash into you, you have bigger problems than the sign can solve.