As it says I think this needs to be addressed by Epic! There is a slight possible Karen Traviss could cover this in the slab! If not then as a dlc it would be incredible! Marcus n Dom with 2 other Gears (pick ur choice) fighting and defending Ephyra during the locust invasion! Also witnessing the fall of the house of sovereigns and playing as Marcus leaving his post to save his father!
Start off in Ephyra defending the city under heavy locust attacks
Marcus leaves his post with Dom
Make your way to the Fenix estate
Witness Adams apparent death, Marcus' imprisonment and the onyx guards kidnapping Adam
I know we played this is gears 3 in Marcus' dream but we could have more this is a big part of the 3 games for me, something that was only mentioned in the book for gears 1! I believe playing this would be incredible remember Ephyra was the capital city of the Coalition and the nation of Tyrus during the pendulum wars, to witness its fall would be an incredible dlc