Yea you can go and just kill it solo but bringing one or two guys(either WAR or WHM is good) is best, it minimizes unexpected deaths.

When you go into the Ruins, they are in EastSarutabaruta the north east one, go in and then the place will be like a square inside, go into the back area and into that cracked wall, but not where there are gizmos, that isnt ur area yet, once you go in talk to the black wall, go through cutscene, but remember to keep some ppl not in the scence, or you can be mobbed once its done, keep one guy at least to fend of everything if it respawns, then go to every gizmo and find an orb, its random so check it all, after that go back to teh Orastary and then the guardhouse, ur done.