The news has been broken from the Arrow official twitter! This year’s cross-over which will introduce Ruby Rose as Bat Woman will be known as Elseworlds! Traditionally Elseworlds was the publication imprint for DC Comics that featured stories that took place outside the DC Universe canon. The Gotham by Gaslight graphic novel, featuring Batman, is considered to be the first official Elseworlds story. Whilst the first book to actually feature the Elseworlds logo was Batman: Holy Terror in 1991.
So perhaps we are out in the multiverse for this one?