In Another World With My Smartphone: Volume 3 by Patora Fuyuhara

Stalwart as ever, 16-year-old Mochizuki Touya heads off to the far eastern land of Eashen with his party in tow. For what purpose? The Matriarch of the Fairy Clan wishes to delve into some ancient ruins, of course! But it's never quite that simple for Touya and his friends, oh no. The party is thrust into the midst of a clash between the warlords Takeda Schingen and Tokugawa Ieyahsu, while a nefarious necromancer makes his move in the shadows...
Throw in a Gynoid or two, an ancient legacy, another ridiculous summoning pact, and you've got yourself a brand new recipe for disaster!
Once more the sun rises upon an epic tale of sorcery, smartphones, and floating cities!