I suspect that there's some confusion either in your interpretation of the adapted edition (depending on what is hidden by the ellipsis) or by the adapted edition itself.
The beginning part of the quote is almost exactly what is in Aeneid VI.264-66. The complete sentence (including two lines afterwards) is as follows:
Di, quibus imperium est animarum, umbraeque silentes
et Chaos et Phlegethon, loca nocte tacentia late,
sit mihi fas audita loqui, sit numine uestro
pandere res alta terra et caligine mersas.
Note two differences from your quote:
- "Di" is far more common than "Dei"
- Contrary to what you have, this is not something that Aeneas says. In fact, as you'll see when we translate, it doesn't make sense that Aeneas would say this. This is an invocation of the gods by the narrator (i.e. Virgil himself), which is a fairly standard epic convention.
The first two lines are an extended sequence of invocations in the vocative.
O gods, who have the command of souls; and silent shades,
and Chaos and Phlegethon; and wide unspeaking lands of night . . .
A few notes here:
- These seem to be four separate invocations, not equivalent appositives.
- Chaos is here a personified Roman god; Phlegethon is one of the rivers of the underworld.
- Nocte is an ablative form functioning as an adverb: it's more common to see noctu, but L&S labels this a classical usage: "at night"; late is also an adverb: "widely, extensively." Some creativity is needed to translate this well: Fitzgerald, for instance, sees it as hendiadys and translates, "regions of wide night without a sound."
After the invocation, Virgil (not Aeneas!) makes his request:
Let it be fitting for me to relate the things [I have] heard; let it be, by your divine will,
[fitting] to reveal things that are buried by deep earth and darkness.
A couple notes:
- fas (often with dative) is an indeclinable noun referring to a prescription of divine law: it is often used in this way to say whether something is (or isn't) "fitting, proper, allowable, holy."
- The second sit seems to have an understood fas mihi after it as before.
In short, Virgil is asking the gods for permission to speak about the hidden things of the Underworld.