Apparently it will be 5 episodes long, and they have a month of filming dedicated to it:

https://tvline.com/2019/05/16/arrowv...edule-legends/

https://twitter.com/thedctvshow/stat...074563072?s=21

(I don't know if the second source is reliable by the way).

I think this is the biggest crossover yet!

Wonder how many characters will be killed off, or not, but from what I know of the story it kinda has to be a bloodbath doesn't it?