If you think of it that way, sure. But I find Nightblood to fit with Endowment's Intent quite well. It was gifted sentience, and really when it is using its ability it is endowing itself with more Investiture. Endowment is to power or give something, and that cannot happen without an exchange, leaving the giver with less and the recipient with more.
Endowment has seemed pretty confident about being protected from Odium in the letters, but we can't be sure about Autonomy. That does not seem to be the way that Autonomy likes to operate, however.