User blog comment:GrandMethuselah67/World-1: The Neo-Methuselahverse/@comment-4867780-20190618130922/@comment-26322734-20190626001842

"Hard to imagine how they managed to build Sol Longia in such an incredibly hostile environment, especially since they started pretty small at the time in the wake of their decimation-induced exodus."

Sola Longia actually predates the Sol Federation (it was the first colony on Mars, which was formed out of many smaller shantytowns in the late 70s), by the time it became a massive city, Mars was already terraformed. So it wasn't too hostile. By the time the Sol Federation became a thing, the city of Sola Longia was chosen to be the capital since most refugees from Earth were going there anyway, since it was one of the biggest urban areas in the Solar System.

"The Black Spiral and Monarchs only determine who gets powers, right ? And they keep it for life once acquired ?"

Black Spiral is a conspiracy that acts as the "shadow government" of the Sol Federation. They control more than who gets powers - they also extensively control the media and hold great sway over the politics surrounding superheroes in general, and are actually locked in a secret war with the supervillain group known as the Camarilla. Fun fact: the Camarilla actually consists of the first team that Black Spiral created, called the 1st Protectorate. Chessmistress, who is the leader of the Camarilla, managed to pull a gambit that led to the 1st Protectorate getting off Scott-free and forming what is now known as the Camarilla.

The Monarchs are a different story entirely. They're higher-dimensional entities (not eldritch abominations, explicitly, since they are born from the minds of sentient life and thus not alien) that are essentially the source of superpowers. They project their power and "choose" a human, and Black Spiral is sometimes able to intercept and distribute that power to another people or keep the event from happening with a 43% success rate. Keep in mind also that Black Spiral doesn't control what powers are given. The Monarchs do.

"Though given the sheer superhuman death toll from nigh-constant Jotun activity, whoever controls the empowering frequency determines the replacement rate, and thus ultimately how many superhumans there are at any given time."

Exactly. Black Spiral is chiefly concerned with combating the Jotnar and keeping the Monarchs at bay, which is actually why the superhuman population is increasing so drastically, so that there are more neohumans to throw at the Jotnar when they attack.