I think this might work, having looked into the concept a little.
Or possibly "unifying".

And these might help:
"The soul is an immaterial substance, according to Aquinas, but this does not commit him to dualism. He argues that though the soul can be considered to be an intellectual principle in its own right, and, in being the principle through which we gain knowledge of the material or sensory world, we can distinguish it from the body, nevertheless, it is so united to the body that
we say that the man knows, rather than that the soul knows (ST, I, 75, 2 and 4). As Copleston (1955, p. 155) explains in his commentary on Aquinas, the human person is not a combination of two substances, body and soul, but one substance which forms one human person."
http://www2.hawaii.edu/~pesaconf/zpdfs/55ozonlins.pdf

"According to Aquinas, a substance possessed only one form, and its matter was the essentially characterless prime matter. In other words the informed parts of an object – in the case of a living creature, its organs, and the various kinds of stuff that constituted it (in the end, quantities of earth fire air and water) did not possess their own forms, but were informed by the overall substantial form."
http://plato.stanford.edu/entries/substance/

http://plato.stanford.edu/entries/aquinas/