because you have no option to run away or hide from both attackers
Double Check Mate?

because you have no option to run away or hide from both attackers
As soon as the RED is out of equation, there is space for me to block, or run away (as the red queen become grey).
If the yellow move didn't affect the RED with the mate, then yes, I will be mated, but on my turn, I can still move
Notice the move order, after yellow moves, it's green's (your) move but you are check by both red and yellow queens and it's a checkmate. And then it's red's move and he's checkmated by yellow.
As soon as the RED is out of equation, there is space for me to block, or run away (as the red queen become grey).
It was your turn next, so you got checkmated before Red, that's why.

No before or after. When Yellow made the move both players are checkmated.
There is no wait until it somebodys turn in FFA, in team there is so maybe OP got the idea from there that turn-order maters.

Red deserves a report for suspected teaming.
No other purpose of Red's last move other than give Yellow the win.

I don't feel sorry for Blue tho.
Nd12+ seems reasonable and had saved the game by saving Green.
It's FFA and the mate guarantees blue second, so that might've been not played on purpose.

No before or after. When Yellow made the move both players are checkmated.
There is no wait until it somebodys turn in FFA, in team there is so maybe OP got the idea from there that turn-order maters.
Thanks for the input, but by definition, on my turn, I can move, so, how it is considered check-mate?
Don't take me wrong, besides red "teaming", yellow move is brilliant, but:
"Checkmate: a position in which a player's king is directly attacked by an opponent's piece or pawn and has no possible move to escape the check. The attacking player thus wins the game."
So, if I can still move to a safe place, how can it be checkmate?
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So, if I can still move to a safe place, how can it be checkmate?
As soon as the RED is out of equation, there is space for me to block, or run away (as the red queen become grey).
It was your turn next, so you got checkmated before Red, that's why.

Here's a more extreme example of this scenario:
This also makes sense, as they are all checkmated at the same time

right, so if there was any "turn order" when it comes to checkmate, Blue would get checkmated, Yellow would be checkmated, but then Green would be left alive as Blue's king and Yellow's king don't defend the queen anymore...
But as I said, there is no before or after, they all checkmated at the same time.

Yeah i heard of Daniel Rench i think his name is. He banned someone for having 2 accounts so they guy could have a better chance at winning this games. Suspicious activity, Don't really see the point though unless 4player chess is becoming that popular. But what does one really get out of cheating though? I would prefer to say that red was just an idiot and gave mate to yellow, but that move was very stupid. However it's easy to make stupid moves in 4player chess cause the board is so big and we got 3 players going against you! Same goes for every other player! Do the math is like 16 moves to think about every move it seems. I'm sure i'm wrong about the math but you get the picture. I hope that's the case, accusing people of doing something wrong without proof is pretty bad too. Mere suspicion is ok, and ofc calls for investigation. So reporting this is a good idea. Could inspire people to be more aware of the board too! Which in that case we all win.
Dear All,
Please check the following:
https://www.chess.com/4-player-chess?g=1218216-130
Then, yellow moves:
But at this point, I could move my king to m7, and avoid the check.
So, I agree with the 20 (checkmate red) + 5 (double check) + 1 (pawn), but I do not understand why is mate to me as well (green).
Moreover, I didn't got why red decided to randomly sacrifice his queen to eat my pawn... Was it a team idea?