Character creation in City of Mist has one stand out component that should be mentioned. There are no numbers involved in your character description. You don't have stats like Strength or Intelligence. Instead you have what the game calls Themes. Each of these Themes represents an important facet of your character and comes with a number of Power Tags representing characteristics that fall within that Theme. There are four Themes to each character and each Theme starts with three Power Tags and one Weakness. Plus, a starting character starts with an extra Tag and an extra Weakness on one of their Themes.
The way these Tags work is that when the character takes an action, you total the number of Tags that sound like they would make the action easier for the character and get your Power for that action. So if you can use three of your Tags on one action you have a Power of 3 and thus add 3 to your 2d6 roll for that action. You cannot use the same Tag more than once on the same action until the situation changes significantly. So if you've investigated the scene using "Criminology and Deduction" then you cannot do so again until you acquire new information or else something about the scene changes enough to warrant it being considered a new task. Statuses can add or subtract to the Power as well. There is an alternate Grit mode if you find your characters regularly managing high Power rolls.
Gameplay wise, this is similar to the absolute purest original version of FUDGE before things like Skills, Abilities, Advantages, Stunts, Extras, and what-not that have been added on since. In fact, you will find that a lot of the advice in the book on how to manage Tags is similar to many of the best discussions about how to run Fate you can find. However, our concern on this post is with the character creation.
As with so many games that use either Powered by the Apocalypse or Fate style game play, character creation is really a group activity. The sort of crew you plan to play is very important to the sort of character you decide you want. A group of high schoolers investigating weirdness in their school is going to have a very different set of characters than a group of elite thieves or mercenaries and a group of self-proclaimed gods would be even more different. Monster of the Week had a limited version of this in the form of the Histories, but there are actual mechanics attached to PC relationships in City of Mist, which is more the norm in these games. As such, I will posit some other PCs for the Crew Relationship section.
That said, the premise of City of Mist is that the characters are citizens of a city, or rather The City. The nature of this city is left purposely vague. It could be a real city or it could be the archetype of all cities. The default flavor is a sort of noir superhero situation. One of my friends calls it "superheroes in Sin City." Everything is rather murky. You don't name specific places beyond The City, you say Out of Town. You don't discuss World War II, or The Afghanistan War, or the Vietnam War. It's just The War and for all we know could be all of those rolled up into one.
Your character is "rift" which is a game term not an in-universe term. There is no specific in-universe term, a point which the book makes abundantly clear. All the terms like Rift, Mythos, Logos, and the like are things that are specifically used to make explaining the rules easier and the characters will use phrases like "others like me", "special people", "legendary people", "walking gods", or whatever term they have come to favor.
As to what a rift is, it is a person in whom a Mythos has awakened and is trying to live again. This mythos could come from myth, fiction, urban legend, intellectual concepts, real people (living or dead), and any of a number of other situations. As with everything else in the game, the nature of this awakening and mythos is left up to the individual campaign to define. It could be your character is the rebirth of that legend or just that something in their life resonated heavily with that legend and attracted its attention. In any case, the presence of this Mythos creates great power in the character and makes them aware of things the rest of the city never sees.
Example rifts in the game include Enkidu, Don Quixote, Hades, Excalibur (yes, you can be a rift for the legend of a place or object as well as a person or concept), the Dreamtime (which is basically like saying you're the embodiment of a culture's entire mythology), the concept of military genius embodied in the spear, Cerebus, and other such things. There are also more generic rifts such as "oni" or "kitsune". In theory, two different people could be rifts of the same legend depending on how the GM is running things.
Step one of character creation is in determining what concept you are going to be using for your character. I am going to be making a gorgon clearly, but that still leaves some choices. There are three mythical gorgons as well as the general concept of the gorgon. Medusa is the most well known who was raped by Poseidon and punished for that by Athena only to later be killed by Perseus. Stheno was Medusa's most fierce and independent sister who in some stories was a gorgon to begin with and in others was changed as punishment for standing in her sister's defense. Euryale was known for keen wailing cries and was especially saddened at the death of her sister. The gorgon in general is the idea of a woman with snakes for hair and the ability to turn a man into stone at a look.
In the other character creation analyses we've been looking at the generic impression of the gorgon, but that's mostly for the fact that you would not be playing one of the famous originals in most games. In this game you very specifically can be touched by a specific legend so it feels a waste to choose otherwise. So my choices come down to the Wronged Victim, the Vengeful Sister, and the Sorrowful Sister. I am going to go ahead and choose Euryale and assume that the legend of the gorgon awoke in her due to the murder of a family member. As a note, Stheno and Medusa might awaken in people with no blood relation to our character.
This comes to the second step where you choose four themes out of the fourteen available. You have to have at least one Mythos (mythological idenity) Theme and at least one Logos (mundane identity) Theme. The other two Themes you take can be any mix of the two. If you start as a "Touched", one Mythos and three Logos Themes, then you are vaguely aware of the supernatural nature of the world hidden from the other people. If you start as a "Legendary", one Logos and three Mythos Themes, then you are heavily divorced from normal life and highly aware of the mythical nature of the world. If you have two of each, you are called a "Borderliner" by the game. Once again, these terms are game terms only, each rift probably has their own set of terminology. A Greek like this might call them "Heroes", "Demigods", and "Gods", for example. The third step comes when you fill out each of the components of these themes.
Each theme comes with a list of ten questions which you are meant to answer with a phrase of about 1 to 5 words in length. The answer to these questions are your Power Tags. You always have to answer the first question on each theme, but you only answer two of the other questions of your choice. Unlocking the others is a matter for character Advancement. There are also four questions describing Weaknesses of which you choose one. As stated above, a starting character can choose one theme which they are allowed to answer an extra Power Tag question and an extra Weakness questions. Also, yes, having Weaknesses is a beneficial thing, even though they will give you trouble in gameplay for the most part, as that is one manner in which character advancement occurs.
As a note, to start you are only allowed to have one "broad" Tag, by which they mean that most of your tags should be phrased in such a way that they can be contextually limited in use. "Vampiric fangs and claws", will only give you benefit in a limited range of circumstances while "Lucky" is broadly applicable to almost anywhere. Note that this is not a matter of how many words are used. "Elegant" is a single word but contextually is usually associated with social matters and specifically high-society type functions and thus is not nearly as broad as "Lucky" or "Powerful".
The character's four Themes are given titles and then identifying quotes. Mythos Themes have a question, referred to as a Mystery, which is a matter of consuming concern for the character in question. Logos Themes have a statement, referred to as an Identity, which is a statement of belief or personality which grounds the character in their everyday human concerns and prevents them from being swept into the Avatar state at which point they become a willing tool for their Mythos to recreate their legend. As a note, Avatars are generally assumed to be the major antagonists of the setting. These are concerned with character advancement primarily but the general is that if you act against your Mystery or Identity, then the attached Theme will start to "crack" or "fade."
The last element of your Themes is crew relationships. For each of your Themes, you choose one of your crew members that has interacted with it. There are a list of three possible ways your character has interacted with theirs and you choose between those, working out details with the other character. In the end this provides you with a Help or a Hurt in relation to that character. Help and Hurt are resources that can be used to affect the other character's chances at a particular action. There are sometimes reasons to get in your friends' way, but that gets into gameplay so we'll leave it off there.
Mythos - Rift of Euryale
Logos - Championship Archer
Themes: Expression, Mobility, Defining Event, Training
Expression - Represents powers that you unleash to affect and change the world or people around you.
Title - A Gorgon's Sorrow
Mystery - "Why did she take her own life?"
Question A - What is the most common way you use your Mythos to affect the world? A petrifying gaze
Question G - What additional expression, not necessarily related to the main one, does your Mythos have? Venomous snakes for hair
Question I - What attitude do you adopt when expressing your Mythos? Sorrowful rage
Weakness Question C - What happens when you lose control over your Mythos' expression? All who see my face...
Crew Relationship - Peter Darling (Peter Pan) and the way he flies reminds my legend of someone. - Hurt
Mobility - Represents powers that help you to move quickly, easily, and unobstructed.
Title - Serpentine Grace
Mystery - "Where can I find solace?"
Question A - What is your Mythos's most useful form of movement? Speed and Grace
Question B - How do you go into overdrive? Naga-like transformation
Question C - What allows you to avoid restraints or confinements? Double-Jointed Skeleton
Question I - How can you use your powers to restrain others' movements? Constricting coils
Weakness Question B - What happens when you go too fast, too far? Can't change back
Weakness Question D - What residual evidence does your movement leave on you, others, or the environment? A scattering of scales
Crew Relationship - Ursula Wulven (Beowulf) pushed me to go as fast as possible and kept me company until I calmed down enough to be human again. - Help
Defining Event - Represents a pivotal moment in your character's life.
Title - A Sister's Loss
Identity - "Everything paled when my sister died."
Question A - What kind of strong emotion did your defining event leave you with? Sadness and Regret
Question F - What skill or mundane ability did you pick up during or due to your defining event? Empathy
Question H - What approach to life did you adopt following your defining event? Never Again
Weakness Question A - What emotional scar or baggage did your defining event leave you with? I should have known.
Crew Relationship - Kana Yen (Kuan Yin) was there with me when I found my sister's body and helped comfort me. - Help
Training - Represents the expertise you have in a given field.
Title - Gold-Medal Archer
Identity - "I find emptiness as I draw the bow."
Question A - What do you do, or know, best? Incredible archer
Question D - What move, method, habit, or trick did you pick up during your training? Filter out distractions
Question G - What piece of equipment related to your training do you usually have access to? Well-crafted Bow
Weakness Question - Who is after you due to your prominence in the field? Harry Lee, Master Bowman
Crew Relationship - Pythas Tolliver (Mathematics) looks down on my training and it makes me want to punch them. - Hurt