Whenever South Korean beat-'em-up extravaganzas are mentioned, one would think Ma Dong-seok aka Don Lee has all the other stars ... er, beat.

Not so fast. We can now add rapper-actor So Ji-sub (Doctor Lawyer, Sophie's Revenge, Be With You) to the pantheon of screen bruiser demigods.

The short, decidedly unsweet action/crime limited series Mercy For None rests firmly on So's squared shoulders and melancholy gaze as he bludgeons his way through gangsters, hitmen, dirty cops and fixers on a mission of revenge.

The storyline uses familiar building blocks: intergang rivalry, sons trying to prove their worth to their fathers, fathers wanting their sons to lead better lives than they did, gangsters vying for position, betrayal, duty, corruption, and the ever-popular heroic bloodshed.

So plays Kim Gi-jun, formerly a trusted lieutenant of gang lords Lee Ju-woon (Huh Joon-ho) and Gu Bong-san (Ahn Gil-kang) back when they were mere flunkies to a bigger fish.

'Sigh, what a mess. And is that guy sleeping on the job? Oh well, it was time to redecorate and rightsize anyway.'

While helping them take over and split the territory, Gi-jun committed a big breach of criminal ethics (cough cough) and was forced to leave after having his Achilles tendon severed – undoubtedly more debilitating than just taking a little finger, like they do across the Tsushima Strait.

When his younger brother Gi-seok (Lee Jun-hyuk, Stranger, Vigilante), who is being groomed as the Ju-woon gang's next boss, becomes a target, Gi-jun comes swinging back into action.

The culprits seem obvious at first, but it soon becomes evident (to the viewer, if not the clueless principal players in this little melodrama) that a far-reaching conspiracy is afoot.

Mercy For None, based on the 2020 webtoon Plaza Wars: Mercy For None by Oh Se-hyung and Kim Gyun-tae, has all the elements for an engaging study of the interesting relationship among its trope-heavy characters.

Not so fast, there.

From the sparse credits found online for writer Yoo Ki-seong and director Choi Sung-eun, this seems to be their first high-profile project, and they prefer to let So's flailing fists do the talking rather than linger on brooding gangster noir moments (although one shared drink between Ju-woon and Bongsan does fill in the gangland gravitas quota somewhat).

'I like what you've done with the grounds. Odd choice of garden gnomes, though.'

Also, unlike many of its comrades in the K-drama sphere, Mercy For None dispenses with characters who are in there just for comic relief. (One split-second exception being a disposable goon in an early episode who seems to defy all of Newton's Laws of Motion when Gi-jun hits him in the face.)

Heaping helpings of poetic justice are served along the way, with the tale ending more or less how you imagine it should.

Not for the squeamish, Mercy For None is ironically a soothing salve for viewers in need of spleen-venting through the vicarious thrill of screen carnage.

And from the way this one shot to the top of the local charts, that covers a whole lot of us.

All seven episodes of Mercy For None are available on Netflix.