This isn’t the first time I’ve written about Hitman on this site – but whereas previously I’ve reviewed single issues or collections, I’d like to take this opportunity to give a bit more of an overview of the series, and why I think it’s so great – and why it’s one of the most criminally under-read comics classics of the last couple of decades.

As I’ve already said recently, I do think that Hellblazer marks the high-point of Garth Ennis’ career. But that’s because he took an existing character that I love, understood him innately, and told just about the best story anyone’s told about him. In Preacher, meanwhile, he told an arguably even better long-form story – a massive, sprawling epic taking in huge amounts of supporting characters and their interlinked fates – but one that, if it had a major failing, suffered from a slight inability for many readers (this writer included) to fully engage with its lead character. It’s with Hitman, however, that Ennis struck gold in creating a brilliant, complex and downright impossible-to-dislike lead – at the same time as telling a really great, long and involving story.

When the series first kicks off, it’s a curious beast – a bizarre, never-to-be-repeated mixture of DC superheroics (the likes of Batman, Green Lantern and Catwoman all show up in early issues), outright supernatural and street-level pulp brutality, cracking jokes as often as it blows off heads. It’s an entertaining book, but it all feels somewhat lightweight – certainly, at this point it doesn’t feel like it’s going to be come part of a trinity of classic epics on the writer’s CV. Tommy himself, meanwhile, is good fun in a wisecracking, too-cocky-for-his-own-good way, but he too has yet to really write his name in the annals of comic book legend.

As the first ten or fifteen issues roll on, however, there are hints that there’s more going on under the surface than first suggested. A major character is killed off, shockingly, surprisingly early on – and only partway through a particular storyline, to boot. A natural, complicated relationship begins to develop between Tommy (at this point already showing hidden depths himself) and deposed police officer Tiegel (in one issue, played with surprising tact and restraint from the writer of The Pro, we learn that Tiegel’s first, ahem, “encounter” with Tommy is also her first with anyone). And with the six-part “Ace of Killers” storyline, there’s a hint of stakes-raising (not to mention a brilliant, brilliant guest-starring spot from Catwoman, who Ennis writes superbly).

Something happens, however, about halfway through the run, when we hit “Who Dares Wins”. Although this arc feels at times like it’s throwing in all the familiar Ennis elements (not only do we open with a group of SAS soldiers under deep cover in Northern Ireland, but for the first time we explore Tommy’s background as – like John Custer before him – a war veteran, only this time Gulf rather than Vietnam), it’s also a shocking storyline that completely shatters Tommy’s faith in his own invincibility, and provides a strong counterpoint to the more surreal elements that would creep into the book from time to time. From then on, there’s a sense that the whole tone of the series has changed – the jokes and weirdness still pop up, but in stories like “Fresh Meat” and “Superguy” the daftness feels like it’s intruding on the growing tragedy that Ennis is piecing together.

And “tragedy” is certainly the theme of the second half of the series; whether it’s the utterly brutal two-part “Katie” storyline that tells us Tommy’s family origins (and yes, that one’s about as Ennis as it gets, too), or the magnificent “For Tomorrow”, which sees another of the book’s long-term cast die, the ominousness never really lets up. It all comes crashing to a head with “The Old Dog”, which provides the inevitable moment you never really suspected he’d get round to putting us through – and which also has as its coda a brilliantly bizarre single issue (#50, appropriately enough) set fifty years after the story’s end. It’s after this point that the series takes a slightly disappointing turn, though – the final arc, “Closing Time”, is a curious mess which lurches into a story that feels somewhat out-of-place with everything that’s gone before, and introduces an almost overwhelming range of new characters at the last minute (including a somewhat unconvincing new love interest) in a way that feels like Ennis squeezing all his leftover ideas into the eight issues he had left.

Still, the final issue absolutely hits the right emotional notes, as Ennis’ final issues always do – and the fact that it does shows just how much the reader comes to love the characters and world he builds over the preceding 59 issues. It’s a remarkable little series, one that will never have the critical cachet of something like Preacher, but which has arguably got a lot more heart to it – those precious few of us that have read it from start to finish tend to hold it in the sort of affection reserved for very few, very special comics indeed. Part of that is down to the way Tommy’s character grows on the reader – not just due to his winning charm, but also the genuine struggle of a man who has a strong conscience yet has only ever been good at killing. Ennis is never afraid to show the dichotomy of Tommy’s character – nor to question whether he really has any right to consider himself a “good guy” for only killing the “bad” – but it’s the flaws that make him such a rounded and engaging character.

It’s a tricky series to catch up on – which does at least explain why so few people have got round to reading it in its entirety. Inexplicably, despite its immense critical acclaim, DC have never seen fit to collect the whole thing – the original set of TPBs only got as far as “Who Dares Wins”, but last year they finally began the process of putting the whole thing out by starting to reprint the initial five books, with a pledge to collect the rest in sequence too. So far the first two volumes are out, and I honestly cannot recommend them enough. If there were any justice, Hitman would be talked about as one of the absolute classic comics of the Modern Age – as it is, we just have to contend ourselves with it being our special little secret.