“He who shall save us”
If this is indeed what Richard replies to Ilana in Latin, then it seems to me then that the one that shall save them may perhaps be Locke (the real Locke)
As if Ilana was asking Richard the answer to a saying or a proverb or some such thing that is known to themselves or amongst the others, and then upon the answer presenting the body of Locke as proof of said saying, with his body literally laying in the shadow of the statue.
How the real Locke could therefor save them I do not know, other than the possibility that Jacob could provide him with life as he lays dying, or perhaps transfer his life force to Locke upon his death.
Maybe something similar to this happened with the “nemesis”, as he could have somehow assimilated with the dead Locke or something.
Blah, I know not.