The Ancient Ruins are found in the mountains near a river west of Saronia. You can find it by following the river from Saronia, turning east at the first fork and west at the second.
There are a number of Dividing enemies on the lower levels of the Ancient Ruins, and you don't have access to any Dark-elemental Weapons yet, so you'll want to bring along characters that can attack with magic or make powerful single attacks to take down enemies before they can Divide.
There are a number of Dividing enemies on the lower levels of the Ancient Ruins, and you don't have access to any Dark-elemental Weapons yet, so you'll want to bring along characters that can attack with magic or make powerful single attacks to take down enemies before they can Divide.