When last we saw Landor, Maker of Monsters, he had just been exploded along with his castle and giant mosquito minions. But did you honestly expect a simple thing like a huge explosion to stop a villain of Landor's calibre? No! He merely becomes more burned up and crusty and bitter! Landor has not shifted his goals since 1939 and is consumed with the twin urges to 1) make monsters and 2) get revenge on Tony Torrence and Marcia Merrill.
Landor makes his dramatic return at the perfect time: US officials, including Landor's old foe Anthony "Tony" Torrence, are completely unable to deal with the menace of the Fire-Men. This gives Landor the perfect opportunity to get Torrence under his thumb, using the power of patriotism!

As usual, Landor has not rested on his laurels. Rather than trot out a version of one of his prior creations, such as a frankenstein or a giant insect or a surprisingly flammable woman, he has dipped his toe into the twin fields of robotics and cybernetics to produce a giant robot powered by a human brain! A fireproof one!

The brain-bot disposes of the Fire-Men without a problem. Well, I
say without a problem, but in fact there is one tiny hiccup in Landor's plan: the cyborg is not strictly 100% fireproof after all, and the Fire-Men's last desperate flamethrower attacks end up driving it berserk and it makes a murderous beeline for Landor and Tony Torrence. Torrence manages to destroy it by luring it into an electrical substation, and since he has saved Landor's life he is forced to relinquish his claim over Torrence's. Foiled by his own sense of honour!
In
Speed Comics 005, Landor accepts a commission to help a couple of foreign agents rob the US Treasury. Being the Maker of Monsters that he is, Landor proceeds to create a giant mole to aid in the tunnelling process. This escapade ends with Tony Torrence gunning down the agents and collapsing the tunnel on top of Landor, but the "IS LANDOR DEAD?" cliffhanger lacks a bit of oomph as he is in fact standing next to the giant mole when last seen.
If Landor had given up his quest for revenge following the giant cyborg incident then the tunnel collapse brought it back in force, and so in Speed Comics 006 he puts a very strange revenge scheme into motion: he creates the Cat-Girl, a two-foot-tall human woman with the head of a cat, and uses her to kidnap Tony Torrence's niece Gloria as a test subject in an experiment to see if he can turn a human being into solid diamond. I'm a bit winded just typing all that out.
Tony Torrence of course rushes Landor's castle just in time to rescue Gloria and deal with both the Cat-Girl and Landor using his new fighting technique: throw your opponent at the nearest solid object. Landor of course survives though the Cat-Girl is not so lucky.
Speed Comics 007 introduces eminent biologist Dr Sina Zurat, who has long admired Landor's work and wishes to join him in it.
Together, Landor and Zurat create the bestial woman Creeta, and at some point along the way the two fall in love! Could a stable home life and a loving partner who gets all of his jokes about gene-splicing finally cure Landor of his antisocial ways? We will never know, as poor Creeta was seemingly born already in love with him and only gets about an hour to grapple with having feelings at all, let alone powerful ones. Consumed with jealousy, Creeta attacks Dr Zurat.


Tony Torrence of course shows up in time to stop Creeta (by turning a screw on the side of her neck that is attached to her steel wire nervous system - a particularly grisly failsafe!), but too late to save Zurat. And here is the point, I reckon, where the Landor/Torrence relationship could turn around. A little compassion from Tony could show Landor that there is a better way to live than in a constant cycle of revenge and biological constructs. Instead, Tony is a huge jerk about the whole thing, ensuring that the cycle continues.
Landor's final four appearances are exclusively revenge-oriented: in Speed 008, he goes with what he knows best and makes a humanoid monster, but unfortunately for him, he drops the dang thing before it's finished... cooking?... and so ends up as a classic Igor rather than the Adonis that Landor had intended. Still, any creature in a storm, and so Ganda, as this particular creation is known, is sent to capture Tony.
Ganda goofs and brings back Torrence's house guest, criminologist Kung Fu Tse (sadly just a name in the "mash together a lot of vaguely Chinese-sounding syllables" mode and not a 70s style martial arts master), but that turns out to be okay, as it turns out that Landor, Tse and Torrence all went to the same college and that the beefs between them began back then.
As usual, Tony shows up in the nick of time, and while Landor escapes unscathed poor Ganda is not so fortunate.
Landor's revenge plot in Speed 009 involves kidnapping Marcia Merrill and injecting her with a chemical to make her blind. It's not a particularly great plan, and Landor absolutely should have seen the end result coming: Tony beats him up until he gives up the antidote to the blindness serum. There are however two points of interest in the story:
1) Landor's chosen henchman for this one is the fantastically-named Stumbi the Fish-Man. It's like I always say: if you're going to be a biological construct created specifically to kidnap people off of boats then you might as well get a great name out of it.
2) From this issue onward Tony Torrence is instead called Jack Torrence, for no clear reason. Is it simple loose Golden Age continuity standards? Burgeoning anti-Italian sentiment relating to WWII? Something else? No idea, but what it certainly is is annoying, though mitigated slightly by the fact that it's almost the name of the guy from The Shining.
Landor's lowest moment comes in Speed Comics 010, as this is the issue in which he doesn't make a monster at all. At least unless you stretch the definition of "monster" to include a prominent criminologist who has been kidnapped and mind-controlled into a willing participant in a plot to frame Tony "Jack" Torrence as a jewel thief. And I do not do so.
Tony ends up spending most of this issue in jail, so Kung Fu Tse is the one who hurls Landor into the nearest hard surface before freeing criminologist John Powers from the mind control.
Speed Comics 011 marks Landor's final appearance and fortunately for his reputation he does in fact make a monster in this one. Specifically, he tricks fugitive Spike Hart into accepting a job and some free plastic surgery and then proceeds to turn him into the Tiger-Man, i.e., Spike Hart with claws, oversized fangs and little stripes on his face.
Sent to bring back Torrence alive or dead, the Tiger-Man comes closer to actually doing so than any creature since the Brute, way back in Speed Comics 001. It is not to be, however, as he ultimately meets his end at the hands of Torrence's butler, a truly ignominious fate.
As often happens in stories with recurring villains, Landor's final appearance was not written as a final appearance. Tony/Jack socks him out the window and he scurries away into the night to get ready for their next encounter, which will never happen.
ADDENDUM: As I was about to publish this it occurred to me that Landor is of course a revenge killer, albeit one with a terrible score. Counting up all of the various attempts on Tony, Marcia and Kung Fu's lives over the course of his career, he ends up with an abysmal final score of 0/9.