I copied and pasted the link from Google Play that you provided but i can't find a Kairosoft game that is named "Kingdom Adventures"... Specify the game's name please (or provide me with the apk in case a game with that name exists and it's not available in my country) so i can attempt to mod the one you are looking for.
EDIT : I apologize,i just saw that it's "Kingdom Adventurers" and not "Kingdom Adventures" like i said...Guess i need glasses LOL.Still tho when i copied and pasted the link the game didn't pop up,only when i manually searched it.
I hope it can be made to be played offline as well... I heard from my friend that you need internet to START the game but you can turn your data / wifi off after the game has been launched...