It seems Lucatiel is stalking me, and she admits as much when I find her hidden in one of the caves down here, saying she was tempted to kill me and take my souls to prolong her own time. Instead she assists me with fighting the boss of the area, who happens to also be the sculptor of these statues - a massive writhing mass of bodies called the Rotten. It flattens me a number of times before Lucatiel and I finally defeat it, earning me the third "great" soul.
A monster with a hobby: Sculpting.
Beyond him is a strange altar which warps me to a new zone but giant locked doors prevent me from advancing further. Before leaving that pit, Lucatiel advises that there are other hidden paths below which I go looking for, encountering and slaying three club wielding giants in the process. Proof that "the last giant" was also inappropriately named. There's also a strange old guy in a wheel chair down here but he's not very helpful so I just leave him there and warp back to the poison assassin forest to see if I can now explore a higher area where the staff and whip mummies were previously kicking my ass.
The answer is yes, mainly because I find Creighton the axe man and a ninja named Bashful Ray to assist! After clearing them and crossing a long, rickety rope bridge (which I managed to fall off once due to carelessness), we slew a tough red guard at which point Ray used his ninja skills to vanish. Creighton and I continued on to face a skeletal chariot! The death machine just made rounds while it patiently waited for me to kill the necros and their bone minions, then shut a gate on its face. With caution I managed to slay the bonemare after that. Alas, Creighton did not survive.
The red guard was worse than the chariot.
Maybe he is from the Elder Scrolls?