Breakdown of Da guerriero, lui viene custodendo la saggezza del re.
lui
he
venire
to come
del
of the; than the (di + il)
da
as a (child/teenager), when one was
Questions & Answers about Da guerriero, lui viene custodendo la saggezza del re.
Why use viene custodendo here instead of the usual sta custodendo?
While stare + gerund describes an action happening right at this exact moment ("he is guarding"), venire + gerund is used for historical continuity. It describes an action that started in the past and has progressed gradually over a long period up to the present ("he has been guarding"). It often carries a slightly formal or elevated tone.
Could I use the passato prossimo (ha custodito) to mean "has guarded" instead?
Yes, but you would lose the progressive nuance. Ha custodito simply states the fact that he guarded the wisdom. Viene custodendo emphasizes the ongoing, unbroken process of guarding it over a stretch of time.
Why is da used in da guerriero to mean "as a warrior"?
The preposition da is often used to indicate the role, function, or capacity in which someone acts. Here, it translates to "in the capacity of a warrior" or "as a warrior". This is the exact same structure you've seen in phrases like da bambino (as a child) or da grande (as an adult).
Is the subject pronoun lui mandatory in this sentence?
No, like most subject pronouns in Italian, it could be dropped. Including lui adds emphasis. It stresses that he specifically is the one acting as the guardian, perhaps contrasting his role with someone else's in the broader context of the story.