So you want to play a human?

Humans are the default Scarterran race. They are vanilla, a blank canvass. A blank canvass has no meaning but at the same time it has infinite meeting. A blank canvass can become anything. A human character can adapt to any character concept you can dream up.
In most cases if you want a Scarterran character based on a popular media fictional character you like, it is usually easier to use a human as the baseline if you want to play an ersatz version of Van Helsing, Samurai Jack, Conan the Barbarian, Arya Stark, Black Canary, or almost anyone from pop culture because most pop culture characters are humans or at least human-like.

Commissioned Scarterra Air couple by Diana Rahfoth

Elegant in their Simplicity

Commissioned Scarterra Earth couple by Diana Rahfoth

The Scarterra d10 system is built around human beings being the default. That means humans have no innate special powers but they don't have any weaknesses either and start out with their full freebie point allotment, freebie points that you can use to buy magic, or more Attribute points, or more Ability points or magic, or Merits.
A player is not expected to know everything about Scarterra as a setting or Scarterra as a ruleset but you should have a good grasp of what your character can do and what his/her background is. If you are a new player to Scarterra or d10 based RPGs in general, playing a human gives you less to keep track. If you are an experienced and you want to play some one with highly unusual powers or a highly unusual background such as a Spirit Loa or a half dragon legacies or a Warlock with a slew of crazy Merits and Flaws it is often easier to paint these exotic traits on the simple canvass that is a human.

Setting Immersion

Most of the time, not all of the time, but most of the time, Scarterran adventures are going to take place in or near lands where humans are the majority race.
This means two things. First, your character can usually blend in with the crowd easier most of the time barring extenuating circumstances. Second, you have a lot more options for picking your character's homeland, family, social class, training background, and the like. Social Merits and Flaws are a useful storytelling tool for any player character but human PCs have more options here so you have more options.

Commissioned Scarterra Fire couple by Diana Rahfoth

Commissioned Scarterra Water couple by Diana Rahfoth

If the game is political or intrigue based in nature or even just a little pollical, you'll want your character to have some ties to at least one or two wider groups and it is easier to justify this for most human characters.
There are more nations and tribes to choose from for human characters than other characters. Also, pretty much every single religious faction, criminal cartel, guild association, and political interest group has human members, so your character can have friends or enemies in a wide variety of groups. Even groups such as the Elven Empire has a large human minority. The Mondarian humans are tightly integrated with Mondarian dwarves. The Order of Delas may be run by gnomes for gnomes, but it does have human members. The point is, you can fit humans pretty much anywhere, even places where humans are the minority.

Core Character concepts

The four basic, so you want to play a ______ articles use humans as a baseline, so there isn't as much to say as with the other race based articles of this type.
That said, because humans are the baseline, you can narrowly focus on the character archetype to fine tune how your character handles his/her niche slightly easier than with a non-human character. Also, if you want to play a character that straddles two or more of these four niches, it is slightly easier with a human than with a non-human in most cases.
So you want to play a warrior?
As a human, you don't have any racial abilities to play into or weaknesses to mitigate so I would recommend giving extra attention to the Advanced Training Merits and consider your weapon choice and specializations very carefully. Your fighting style will define your character's memorability very much as you likely cannot lean into your character's exotic heritage.
So you want to play a Rogue/Expert?
Not much to say here, but all things considered, a human character is probably going to have an easier time justifying a wide assortment of rare abilities than a non-human.
So you want to play a mage?
Not much to say here, but with nothing draining your freebie points or with innate weaknesses to work around, that frees up more freebie points and experience to take more magic at character creation. Also, as a human you have far more magical tradition options than most non-human mages since most non-human cultures are closely tied to a smaller subset of mage traditions, often to the exclusion of the others.
So you want to play a divine magic caster?
Most non-human races come from a culture that strongly suggests what religious groups they can join. If your non-human falls into an unorthodox religious group, they can get some pushback from the society of their birth. Humans don't have to deal with this as much. A human theurgist can easily justify being affiliated with any religious groups without raising too many eyebrows though you still have to deal with the traditional rivals of whatever religious group(s) you are a part of.