This is a Custom Magic the Gathering set based on Fate/Grand Order. The set is the first in a planned block of three. The block is called the "Fate" block, and the first set is simply called "Fate/Grand Order". Naturally, this set may feature spoilers for F/GO and related properties.
In general, the set is heavily combo-oriented, with cards specifically designed to work with each other.
Yes! Using a program called Cockatrice, you can play games using these cards and even combine them with existing MTG cards as well. They're fully compatible. You just need to make sure the person you're playing with has downloaded this custom set as well, and you're both using the most up-to-date download.
This first set includes every single Servant released up to the end of Part 1 of the F/GO storyline. If your favorite Servant was released in Epic of Remnant or Lostbelt, then it will show up in the later sets when I eventually get to those parts.
I did my best to balance making the colors accurate to character personalities and also making them accurate to what that character is capable of, gameplay-wise. Sometimes I had to make a few compromises in either direction. I'm open to feedback, but a lot of thought was put into the existing colors and there may not be much wiggle room left to tweak colors too much.
Tying a Noble Phantasm's effect directly to a creature on the same card would have made creatures way too wordy, so I separated them into separate cards. All versions of a Servant can use them (for example, Artoria Lily can use Excalibur, and all versions of Hassan can use any other Hassan's NP) because I felt this made for a more versatile set that was more fun to play. Limiting them to only being usable by one card each would have made for a lot of dead draws and unusable cards in your hand.
I wanted Noble Phantasms to feel powerful in general, and my main priority is that the set is balanced within itself and that there are viable options in every color. I'm not overly concerned right now with how balanced it is with the rest of the MTG card pool, as there are already tons of broken cards in MTG. That being said, the set is still undergoing playtesting and I will be making tweaks to ensure nothing is overtly broken to the point of being unfun.
For World Enchantments, it was because I felt that was the best mechanic to represent Reality Marbles and similar abilities in F/GO. It fit too perfectly. I also gave World Enchantments their own new card frame with full art to make them a bit more exciting. As for Cumulative Upkeep, at first it was because I wanted to emulate the fact that Reality Marbles aren't meant to stick around for long. But I later realized that there were interesting ways to use the mechanic on other cards as well. Since it's a bit of a faux-pas to include more than one type of counter on permanents in a set, trying to find ways to use age counters in place of other counters like +1/+1 or -1/-1 counters made for an interesting design challenge. In order to avoid the nightmare of having to keep track of all sorts of different cumulative upkeep costs, all cumulative upkeep costs in this set are counted in 1s. I felt this was no less manageable than keeping track of how many times your Commander has died, for example.
There are too many characters in Fate whose abilities, myths, and legends revolve heavily around gender-based interactions. I felt it was very thematically fitting and it made for a fun mechanic. From a strict rules perspective, if a card does not have a gender printed on it, then it's genderless. That would include all cards outside of this set. However, in reality, if Wizards ever added a mechanic like Gender, I imagine they would probably errata older cards to have them, based on their existing lore or card art, so if both players agree beforehand, you could houserule older cards to have genders if you were mixing older cards in. Officially, however, cards only have a gender if they're printed with one.
Classes don't really do anything on their own outside of being a new card property for other cards to refer to, but I felt I couldn't just leave them out, since they're so important to FGO. I'm working on some optional rules that would grant all Servants of each class particular class abilities. As for the existing "Classes" of MTG, that was always a more colloquial thing to refer to certain creature types. The word "class" doesn't actually exist in the rules, and I felt the word was too important to FGO to use a different one.