2, a hero emerges

As the world is on the brink of destruction, a hero arrives to stop the tide of monsters and magical races overwhelming their planet. This hero's name is Rubicon, and, although he reversed the tide of invading enemies, the planet was still destined to die.

• Declining birth rates
• Pollution
• Desertification
• wealth disparity
• Threats of nuclear armageddon
• Asteroids threatening to doom the planet in one way or another
• Diseases
• Abuses of power

There were far too many problems for Rubicon to simply leave to doom humanity, so after going to where the magical enemies came from, Rubicon enslaved several races to do various tasks for him:

• Succubi were made to feed off semen donations and get impregnated with one baby after another. Rubicon was also a bit of an eugenics guy, so he made sure they didn't debase themselves for the closest man and picked worthwhile specimens.
• Elves protected tribes while healing ecosystems, becoming nannies to countless animals and gardeners to plants. Elves also greatly improved food production worldwide.
• Monsters were given powerful abilities from high-ranking enemies on mass, creating weaker variants like the power known as the sin of gluttony being used on monster hordes to devour all the plastics.
• Vampires infiltrated governments and organisations, taking down corrupt elements and dictatorships.
• Dwarves created critical infrastructure or special devices to counteract several natural disasters or threats. They also created golem legions meant to take up roles for the public that required far too many workers, like those helping soup kitchens, building homes, or cleaning streets.
• Mermaids created strong water currents at various levels of the ocean, allowing ships to get around faster without the use of fossil fuels, as well as creating a submarine shipping industry. They also restored ocean currents that acted as natural temperature regulators for the planet.
• Seraphim made celestial arrays for people to traverse across the planet, visit nearby worlds and moons or simply gaze at them, and take away any kinetic **** from incoming masses like asteroids, allowing them to gently land on the planet for harvesting.
• Demons acted as devil advocates, improving legal systems, on top of offering boons of power, improving physical, magical, or mental features of contracted creatures. Seraphim also got in on this, but they weren't as prevalent as demons and didn't want to potentially encroach upon Rubicon's wrath.
• Orcs repaired structures or became the main labour **** for great projects.
• Beastmen were turned to becoming mostly trainer-oriented, creating cheap or free gyms and tutoring sessions that brought up the world's health and made a lot more people fit.
• Dragons created magic towers that they tied their lives to, often shedding or ripping parts out/off to sustain them, a painful but minor thing since they have supernatural regeneration.
• Yetis and ice/cold-type allies refroze glaciers and created fantastical works

These many races helped recover the planet and improve upon it, allowing Rubicon to take a back seat as he saw these bound races began to love their new home.

• Succubi didn't have the same selection and right to suck someone dry but they drank plentifully and created great houses of clans where even the ones considered small still raised 100s of human children at a time.
• Elves grew strong bonds with the nations they helped and the tribes that had a similar respect for nature, causing many elves to develop romantic relations.
• Monsters quickly adapted and evolved thanks to the great powers embedded in their bodies, causing them to go on a plastic-only diet or transform the plastics into blocks of raw materials to be recycled. They also had fun mixing their genes with local species, causing many animals, insects, and whatnot to become beefier or more ferocious.
• Vampires still had their machinations, but now a lot of them saw themselves as pillars of righteousness that oversaw the childish humans playing politics that the vampires mastered long ago.
• Dwarves loved their lives as prized artisans with much fame.
• Mermaids set up new kingdoms or enjoyed riding the powerful current tunnels that were constructed.
• Seraphim realised a splinter colony they lost long ago had been the ones depicted in Christian mythos and decided to see Earth as a second home.
• Demons loved the progression of humanity and the many souls willing to make bargains, even though the deals didn't allow the demons to keep human souls for eternity.
• Orcs had many women and whores unlike their original world that used to have a small population doe to the many long-living races or ferocious beasts they needed to fight to keep their race going. In this new world, love could bloom, and an understanding of consent over conquest war was established.
• Beastmen regularly fell in love with humans like a lot of the other races, becoming entranced at the way humans went from weaklings to strong men and women that, although they weren't as powerful as beastmen, were still admirable and attractive.
• Dragons disliked the crappy selection, but the large range of potential disciples made them enjoy teaching magic and feeding their egos that they were usually stuck gloating to themselves about.
• Yetis often made homes in the tundras where they expanded and saved, living alongside penguins.