Is Hermaeus Mora just lying by calling the Dragonborn his new servant, in the hopes that the Dragonborn will believe it, and put themselves into actual servitude?

Should be in the Spoilers section of the forum. Reporting for transfer now.

The player's actions to that point have served Mora's purposes, which is all he means. He'd like it to mean more.

Hermaeus Mora is my favorite daedra, not prone to extreme fits of bipolar behavior like Azura is. If it weren't for the fact that Miraak's stuff is too... Miraak? Then I'd definitely create an apocrypha-themed character. that would serve Hermaeus Mora. I might just do that actually.

You are a servant of everyone, in one way or another. This kind of talk is mostly just bravado and antics. Don't pay attention to it.

^This doesn't count just for Hermaeus Mora.

Apocrypha the realm of Hermaeus Mora and pretty much all realms of Daedric princes are the daedric princes themselves--> When you travel to Apocrypha you are not traveling to a place in some weird dimension, you are traveling inside Hermaeus Mora. So in a way anything you collect in that realm, this includes: gold, gems... and knowledge of course, is taking a part of Mora itself with you when you come back to Tamriel.

So if you pick up a Black book skill or a simple Spell book in Apocrypha and learn the spell--> That knowledge you just acquire is putting Mora itself inside your mind, by your own free will. Of course this truth could traumatice you, so the game just makes you think you are "Special" and nothing bad can EVER happen to you.

If you thought something given so willingly like the skills of the Blacks books or the Oghma Infinium by a Daedric Prince no less, was really "Free". Well, you were wrong, or simply don't read the little books in the game like "A tragedy on black" :].

Here is also something to keep inmind. Hermaeus Mora will just sit back and let events unfold. Berhaps it is because he is the daedra of fate and knowledge? Who knows, but my point is... you can tell him to go svck a lemon and he ordinarily wouldn't bother with you I'd imagine.