The Roman Tomb lies just outside the south-western corner of the ancient walls. It is a small underground family tomb rather than a grand monument, but it gives Hisarya's Roman story a more personal scale after the walls and baths.
Check local opening conditions before making a special detour, as access can be more limited than the open-air ruins. Even from outside, it helps explain the ancient city as a lived place, with suburbs and burial grounds beyond the fortifications.