Invaders of the Rokujouma!? Volume 35 by Takehaya

After the attack underground, Koutarou and company return to the surface to regroup and plan their next move. They know Ralgwin will continue to come after them as long as he still has a hold on Earth, leaving them little choice but to mount an offensive of their own in an attempt to put Vandarion’s coup to bed once and for all. Fortunately, they have a little extra help on their side with the arrival of Princess Nefilforan, known throughout all of Forthorthe for her military and martial might.