A word for someone who "imbues"

The agentive suffix -er can be applied to almost any verb to make an agent noun. Even if the agent noun has not been invented yet, any native speaker will understand it if he knows the corresponding verb. Currently existing examples include the following:

to fight + -er = fighter 'one who fights'

to play + -er = player 'one who plays'

to work + -er = worker 'one who works'

Your invention, imbuer, also fits into this paradigm. In fact, people have probably already been using the word for some time, albeit not enough for it to be included in every spell-checker's dictionary.

to imbue + -er = imbuer 'one who imbues'

If you want to use it, use it! Invention is the heart of language.

Consider endower

Endow means

to furnish, as with some talent, faculty, or quality; equip: Nature has endowed her with great ability.