Swordbringer
Let's illustrate 3 points as the Author already clarified 1. Arthas losses Valyerixn sword 2 . It's not the sword ,it's the wielder 3 . Secured Cersei Lannister loyalty Going by these 3 points Robert's Rebellion is still happening ,it's just alterations for Arthas being , but I don't know about the Prince who wax Promised Jon Snow birth ?No he's not nerfed, but Arthas lost a powerful weapon ,and he got his skills and super human physic. Though , Heads will roll or be on spikes as revenge is a good motivation for Arthas and Cersei Lannister . Considering that Arthas is getting Sif back on way or another in the future .Continue on Cheers!