Eventually, Ipaxalon feels grounded enough in geopolitics to take a more active role in things other than ending slavery. 

He still waits until he's got a proper lair set up, with trusted allies as guards, because this next step is about to make some enemies. 

He makes it known that one or more sides in a dispute can request his intervention, on the condition that whoever does so has to agree to a ceasefire (if actively warring) and submit to neutral arbitration (not necessarily his, but someone agreeable to both sides, and it defaults to him if they can't agree). Any side in any conflict can make the request, but he reserves the right to decline involvement. After he accepts a request, he informs the other party that their opponent is requesting a ceasefire and arbitration and that he intends to enforce both. 

The first few times he is called upon, Ipaxalon has not yet built up a reputation. He is forced to get somewhat rough with the belligerents.

Here's the thing about dragons. They're the iconic monster for a reason. Even by the standards of high-level adventurers, they are kind of terrifying. 

The early 1800s does not really have the means to deal with a dragon. But what about magical girls?

An antimagic field shuts down any and all magic, including spells and supernatural abilities, in a ten-foot radius around the caster, unless said magic is from a very short list of extremely specific counters or literal divine intervention. 

It does not particularly hinder a dragon in continuing to be a dragon. 

So that's defenses pretty well covered. But how does a dragon end a fight without killing a whole lot of people? 

As this institution becomes more well-known, he starts delegating more of the process to a growing staff of freelance diplomats, and steps in only when necessary. This turns out to be important when he turns his attention to China. 

At this stage in history, China is Very Not Okay. Rampant corruption, oppressive imperial regime, frequent bloody rebellions. It's also home to a third of the planet's population. And so, well-prepared with tongues and cultural adaptation, Ipaxalon visits Beijing. 

A few early victories, including a negotiated settlement with Britain over the opium trade, earn him respect in the government. Despite this influence, Ipaxalon's efforts ultimately prove fruitless. There is way too much dysfunction and casual disregard for life in the Qing Dynasty. He reluctantly backs off his attempts to salvage the government, and resorts to damage control. 

At approximately the same time, a famine in Europe causes a flurry of (mostly) liberalizing revolutions. Ipaxalon triages; he instructs his staff to provide harm-minimizing charitable aid, offer arbitration to factions that will accept it, and otherwise stay out of the way. They will negotiate with new leadership when the dust settles. 

Also at the same time, America is attempting to grab as much land as it can. Unfortunately for Mexico, Spain, and quite a lot of native tribes, there is not much Ipaxalon's overtaxed peace corps can do about this. With half the world on fire, they can barely maintain the ongoing support for the abolition movement.  

The mid-1800s are a rough few decades. 

Ipaxalon does manage, barely, to prevent a civil war in America, in part because he's been spending a lot of time trying to make them less dependent on slavery in preparation for a proper uprooting of the practice. He is less successful at dealing with the various abuses of natives, there and elsewhere. Too many small skirmishes, too few centralized authorities to negotiate with. He can make it known that formal agreements between governments and tribal councils will be enforced by irate dragon if necessary, and pay trusted observers to watch for violations. 

And then there's the "sick man of Europe," the crumbling Ottoman Empire. Having learned a valuable lesson in China, Ipaxalon doesn't try to prop up the regime beyond basic advice and mediation. He does what he can to keep the inevitable secessions and splinterings as bloodless as possible.

Meanwhile, theology continues to puzzle him. Those raised from the dead appear to have no memories of an afterlife whatsoever. This is deeply alarming, though not conclusive by itself; there could be a tighter memory interdict in place here. 

Contra his initial impressions, Earth has many religions. He tries praying to every god he might conceivably share values with; none answer.

He doesn't encounter any celestials, fiends, or other outsiders, even when investigating an alleged demon cult. 

When magical means of observing and contacting other planes also come up completely negative, the hypothesis that this world does not have gods or afterlives becomes alarmingly plausible. 

Even speak with soul fails every single time.

Resurrection spells do repair lethal damage to a body and brain, so the soul bit might be extraneous.

Well, that at least settles the question of whether he plans to have children here. He won't take the risk they might vanish forever after dying of old age. 

Magical research proceeds slowly but steadily. He spends enough time in equatorial regions, which are way too hot, that he spends a whole two weeks of crafting time on a page of spell knowledge (endure elements).

He continues to be unable to teach even the simplest spells to mortals, even after teaching Draconic to a trusted researcher, itself an extremely difficult task. It's looking more and more like a project of centuries. 

(It's even worse than that, actually. This particular kind of magic requires a soul.)

True seeing reveals nothing particularly distinct about monsters, magical girls, or the benign creatures they sometimes become. He can't talk to monsters with tongues, and he's not sure about creatures but they don't seem very talkative. He suspects he could polymorph a creature back into a magical girl, at least if he knows who they were before. After some consideration, he tries harder to communicate with them. Detect thoughts and detect desires, coupled with tongues, can actually elicit opinions from them; he discovers the creatures are definitely people and none of them seem to actually want to be changed back. 

He cannot get home, or indeed anywhere at all, with a plane shift. 

So after the utter madness that is the mid-1800s, Ipaxalon settles in for the long haul. 

It's not all work and no play, thankfully. Monster hunting remains a fun public service to perform. There's a market for flying lessons and for performances that take advantage of his various talents. (The rendition of A Midsummer Night's Dream with an actual shapeshifted fairy is quite popular.) And not all of the people on this planet with pretty wings and good hearts have extremely specific constraints on their romantic lives. 

He can fix violent deaths and disease, to a limited degree. He can't fix aging. He mourns the loss of many a friend, but he knows better than to stop making more. 

Ipaxalon does his best to build and strengthen institutions, and to tie countries together tightly via mutually beneficial trade. He persuades many countries to agree to rules of warfare that minimize civilian casualties and encourage arbitration. He only rarely gets personally involved in conflicts, and only when called upon. 

Europe remains a simmering cauldron of rivalries, resentments, and revolutions. Heroic attempts at diplomacy, coupled with regular divinations about imminent wars, manage to keep a lid on things for a while. But not indefinitely. Around 1870, French domination of Europe has waned considerably and the scattered German states attempt to unify, including German speakers in (nominally) French and Polish territory. France objects strenuously and tries to put down revolts in the Rhine. The German confederation takes this as an act of war.

Things escalate rather quickly from there. Britain backs the German confederation and drags in a reluctant Portugal by proxy. Poland opposes Germany over their shared disputed territory. Russia is persuaded to attack Poland. The Ottoman Empire takes the opportunity to vent its anger at Russia. So does Sweden, which is still mad about losing Finland. And so on.

Mediation, arbitration, and damage control efforts proceed apace. Ipaxalon is a Lawful dragon, so he does not unilaterally intervene. But there is quite a lot of treaty-violating massacring of civilians going on, especially by the armies of certain states. The first time, they get a warning and a notice that there will be an investigation and penalties invoked. Generals are told their army will be forcibly restrained if it looks likely to happen again. Sometimes this works. 

More commonly, Ipaxalon pays a personal visit to an army as it's preparing to siege a city and offers one final warning which invokes the treaty to which their state is a party. If the warning is ignored, he proceeds to knock out their magical girls, wreck their artillery and powder stores, scare off their horses, and yoink a large fraction of their rifles with a magnetic field. (These would be the "preventative measures" laid out in Article 17.)

Some states are so bad at restraining their troops, so generally inclined to massacres, or so deeply invested in a war that they decide making Ipaxalon their enemy is priced in, treaty or no treaty, and try to figure out how to kill him. 

Those states lose. 

Mortal technology improves over the decades. A few serious attempts on his life are made, but they do not yet properly appreciate the degree to which Dragons Are Really Tough To Kill. (Especially paranoid warrior dragons with support networks and precognitive spells that nobody knows about.) 

And he's growing stronger with age and experience. 

It is hard to gain class levels as a dragon, but between the spell research, the occasional squashed mortal invasion, and a battle against eldritch kaijus every week or two, Ipaxalon eventually improves his magic. He also practices his shapeshifting, previously a tad neglected, to remove the duration limit. 

By the time a century has passed, Ipaxalon is an ancient dragon with access to eighth-circle spells. 

Ipaxalon does not usually make a habit of supporting secessions, because that would make it exceedingly hard to work with states, but China's government is so thoroughly corrupt that he makes an exception for otherwise functional provinces trying to get out from under them. Ipaxalon accepts several requests made by Chinese territories to negotiate their independence with Beijing; Beijing declines to negotiate, even after several armies are stripped of their war materiel. Eventually the cascade of rebellions reach a critical mass, and China splinters. 

By sheer coincidence, Europe has another massive flare-up in 1914 which is about as bad as the historical one. A resigned Ipaxalon continues his policy of treaty enforcement and damage control; by now his organization includes an international relief fund and a large staff of medical and logistics personnel.

Enforcement gets more complicated. Guns have advanced to the point where Ipaxalon can't simply ignore an army's worth of them. But he now has at-will control weather and plenty of other options for crippling supply lines with minimal risk. For countries that still haven't gotten with the no-war-crimes program, precision strikes on infrastructure replace mass disarmament as the intervention of choice. (Though he will still sometimes overfly a marching column in thick fog and yoink their rifles.)

Thankfully, geopolitics calms down a little after this. The 20th century sees plenty of localized conflict, but nothing on the scale of the last two Great Wars.

With no continent-spanning wars to motivate the development of nuclear bombs, nuclear power actually emerges first. Ipaxalon manages to get most powers to agree not to weaponize a technology that could level cities. Thanks to a combination of divinations and regular intel work, he's able to see this agreement actually enforced.

The Pax Corps is now a continent-spanning organization with a mandate that includes arbitration, treaty enforcement, disaster relief, global health initiatives, and monster control. It's a popular employment option for magical girls, and makes extra effort to recruit those whose powers can replace Ipaxalon's spells or synergize well with a strong support network. Synthesized diamonds make resurrection much cheaper, but this accounts for most of Ipaxalon's more powerful spells most days.

Increasingly, Ipaxalon tests the organization's robustness and ability to operate without him. Its ongoing function still relies fairly heavily on unique magical powers, but they at least grow more distributed over time. A growing array of contingencies, informed by various drills and minor crises, is set up to allow the Corps to operate at reduced capacity in his absence.