Invaders of the Rokujouma!? The Silver Princess and the Blue Knight

After Clan and Koutarou are caught in the premature explosion of the Super Space-time Repulsion shell, they’re blown clear across the universe to a most unexpected destination. Will they be able to put their fight aside long enough to cooperate and figure out a way to get back home? Along the way, they’ll meet some strangely familiar allies and witness the start of a legend firsthand—just not the way they ever expected it to happen. Source: J-Novel Club