Malleus and Ortho do not interact often, and mostly in a Halloween vignette where Ortho uses his database to help Malleus decide on what Diasomnia should wear for their Halloween costumes.
With Ortho’s assistance Malleus decides on longs (“a dragon-like creature from the Far East, revered by humans”), acknowledging that while he is grateful for Ortho’s help, he has “no idea how he did what he did.”
Ortho says that Malleus has told him stories about the Thorn Fairy that he didn’t know, and he is happy to have learned information that isn’t available online.
“Lightning” is what Ortho has listed as his most disliked thing on his profile, and it is briefly referenced in Wish Upon a Star. In Book 6, Ortho is taken out by Thunder spears.
Ortho has a voice line about how he would have to be careful if he met the Thorn Fairy, as he would short circuit if she were to call down lightning out of anger.
Ortho says that he would choose Malleus to go with him to a deserted island out of all the school’s students, because he has heard that the weather on islands can be unpredictable but Malleus is powerful enough to be able to handle lightning strikes: “And I think if I asked nicely, he’d be willing to protect me from them.”
When they meet in Book 7, the over-blotted Malleus greets Ortho with a lightning strike.
Ortho says that Malleus’ magic was able to easily pierce the anti-magic material that is his STYX-developed anti-magic armor plating.
Malleus’ spell takes Ortho’s technomantic cameras and circuits offline so that he cannot transfer in any other gear he has at the school.
When they meet in Malleus’ domain Ortho mocks him with, “One of the top five mages in the world? Ancient magic and arcane realms? I’m not impressed,” which Malleus soon throws back at him, defeating Ortho in a battle and responding, “This is truly the apex of humanity’s technological might? I’m not impressed.”
(The Chief Engineer takes issue with Malleus turning Ortho’s mockery back on humanity.)
Malleus decides to obliterate Ortho, taking out one of Ortho’s Cerberus androids instead. Upon his second attempt Malleus’ attack misses and Ortho reflects, “It’s almost like his CPU is overloaded and his processing power dropped…”
Malleus’ third attempt to kill Ortho takes out the second Cerberus android, instead.
Twisted Wonderland Reference Note 