So I have reached the point where I killed everyone in the brotherhood sanctuary.

Now I take orders only from Drop Boxes and am a silencer.

Is this kind of 'the end' and I can't rank up anymore (Like how in Skyrim you just continuously get tons of quests by the night mother)

Or is there a point at which I rank up higher, or at least speak to Lucian Luchanse again?

(I don't mind spoilers for the questline so you may use them in your answers)

You have quite a lot of quest line ahead of you. The story is just beginning, really.

Ok, Thank you!

I didn't want to just start doing an unlimited number of drop box quests without knowing that there actually is quests after that,

Thanks for the info!

It is not, however, like Skyrim where you have infinite quests.

But you have a fair way to go.

Good luck, some of the enemies are surprisingly powerful...