I've been wanting to have all of Molag Bal's dolmen lines in one place for a while now, and this seems like the perfect place to put it. Here's every dolmen quote I could find. Note that he won't say some of these until after the main quest is completed.
Wretched things, mortals. May a storm wash you into Coldharbour.
You must bow to me or die. Minions, destroy them!
You think this is over, wretch? Tell yourself another lie.
I admire your tenacity, mortals.
Wretches! All my servants are wretches! Perhaps these will do the job!
I give you one chance to surrender. Surrender to your death!
The skins of those you love will fly as my banners.
Yes. Wash the stones in blood. Good.
Man is mortal, and doomed to death and failure and loss.
When Nirn and Coldharbour are one, all will serve my will!
You again? Cease splashing blood upon my chains!
Destroy the body, and the animus is cast into darkness. But the animus returns.
Wretched mortals. Worms.
You are useful little worms.
You've only destroyed my whelps. These minions will not be so easily defeated!
I will dominate this world and all others in time. The strong should always command the weak.
Nothing you can do will end this.
May your enemies be broken and bloody.
While the prey was distracted, the predator prepared to strike.
Your death will mean nothing to me. You are but a minor distraction.
I am patient. But not that patient, fool.
My subjects failed me. They deserve to be destroyed.
When you are destroyed, the flies will pick your bones clean.
Your White-Gold Tower will serve as an anchor point for my dark machines!
How many have you killed to defeat me? Each death is like a prayer to me!
I will ensure no tales are told of your valor.
Unexpected. I will call forth someone more worthy of your strength.
Kneel before me and submit to the power of Molag Bal!
I don't want revenge. I want your submission.
These stones will wear down in time. As you will, mortal.
Fool! Did you think Molag Bal, the Lord of Domination, would be defeated so easily?
Your pathetic attempts to save this world amuse me.
Are you still working for the dim one?
The end of Nirn is at hand. Come forth and destroy!
Destroy this anchor and scores more will take its place!
You entertain me, mortal. Well done. Now, entertain me more!
May your soul burn.
The effort was not for naught. Until next time¦.
Puny mortals, you think you've won? Come, my slaves! Destroy them!
My minions will gnaw the flesh from your corpse.
You have killed many. But I have killed more. Fool, you are outclassed.
The plan is in place. You are but an inconvenience.
That's right. Grind them into the dirt.
Dogs! Filth! You anger a powerful enemy.
You've proven your strength. Again.
Your efforts are futile. The Planemeld is nearly complete.
You think me brutish? How do you imagine I view you?
Your corpse will make a fine addition to my collection. Minions, destroy them!
Your time in my realm made you strong, as expected. Let's see how you fare against these.
They serve by choice. They serve the strong. They serve me.
Pointless. Ten anchors drop for each that is destroyed!
Drink in your victory. It won't last long.
Fool! Every drop of blood you spill to defeat me only gives me more strength.
When oath-bonds are weak, there is pain, and shame, and darkness.
Thrashing you thoroughly will please me, mortal.
We sometimes admire our prey, and secretly applaud when it cheats our snares.
If I cannot control your world, I will destroy it.
You've done nothing, mortal.
I await you at the next anchor.
To challenge me is to die. To flee is to become prey.
You do not yet know fear? I shall make you afraid!
Kill my minions and you only remove the weaklings from my service.
The Daedra. The anchors. You destroy them in vain.
You must defeat me every time. I need defeat you only once.
They serve by choice. They serve the strong. They serve me.
Submit, and become mine! Fight, and be destroyed!
The strong will cleanse the world of the weak. Cleanse, my pawn, cleanse.
I forged you in the soulfire of Coldharbour to be my tool. Prove your worth.
Bend your knee to me, I'll give you a minion for each enemy you've slain. You will have an army.
The time remaining when you can still refuse me is dwindling.
Destroy more. Destroy more. Destroy more in my name, pawn!
Ah, it's my unwitting tool. Return to my realm and serve me.
Good. I grant you permission to strengthen yourself with my minions.
Yes. Sacrifice those servants in my name. Let's give you something worthy to sacrifice!
Your strength will be rewarded. One day.
The plan shall go on, with or without you.
My plan comes to fruition, mortal. You serve me now as a vessel of destruction.
Your soul is mine. I own you! Come. Let us play.
Throw aside the pawns, my knight. Until one day you are taken unawares.
The sacrifices you make are all done in my name. You are and will always be my servant.
Your strength is mine. Come. Serve me.
Varen's gambit nearly handed the empire to Mannimarco and Nirn to me.
Mannimarco was a pawn. You are another. Come. Let's play.
Where has the giantess gone? Back to milk some mammoths?
You and Sai Sahan have much in common except you're not a complete failure.
Where has little Abnur Tharn run off to? Where does he hide?
The King of Worms served me poorly. Perhaps you will do better.
The Prophet is a fool, and you are a greater one for following him.
The Battlemage has the amulet, but you have true power. Fight for me.
Mannimarco's failures are your opportunities. You both shall serve me well.
Where is that failed Sword-Saint now? Brooding in some sandy cave on the edges of Oblivion?
The Tharns and their trinkets. It is weakness to rely on toys for strength.
Lyris Titanborn. She was the best slave at the Black Forge. Whatever happened to her?
Now you face my chosen soldiers. Kathutet, Amkaos, Ranyu! Destroy these worms!
Amusing. Let's see how you fare against these ogrim.
Blood on the water, Velehk this way comes. Your doom is upon you.
The Dremora know no fear and admit no defeat.
You will now be a gift to my most favored pet, Menta Na.
Some prefer knowledge to strength. Yggmanei gives me both.
Some of my pets are fascinated by the toys of mortals. Hrelvesuu, show them!
You've done well. Now it ends. Come, Rhagothan! Feast!
Now face my personal slave. Nomeg Haga, come forth and stop these worms!
Most atronachs are weak. Some are strong. Zymel Hriz, I summon you!
The Xivilai make excellent torturers and guards. Let's test them against you.
The Seducers are known for their subtlety, but I find they have many strengths.
From deep beneath Cyrodiil, I summon Fangaril! Consume them, each one!
From your sanctuary on Vvardenfell, I summon you, Lord Dregas Volar.
From deep beneath Morrowind, I summon the lich Gedna Relvel!
Ozozzachar, my son! I summon you from the skies!
Kathutet, Amkaos, Ranyu! Time to torture some mortals!
Think you're strong? Have some ogrim! Three of them!
He'll tear you open and eat your heart raw. His eyes gleam red, his heart will never thaw.
Many Dremora serve Dagon, but these serve me.
The daedroth Menta Na has served me well. He will destroy you.
For your final test, meet Yggmanei. Even the Lord of Domination needs spies.
Deep in dark Nchurdamz, I found Hrelvesuu. Come forth and destroy!
A mortal for you to feast upon, Rhagothan. You may feed now.
Forged from ice at the heart of Coldharbour, Nomeg Haga will destroy you.
Can you withstand Zymel Hriz, an atronach of lightning and rock?
Xivilai know no honor. Anaxes and Medrike will test their strength, not yours.
Loyalties are fickle among the Dark Seducers. Face now the least loyal but most deadly.
Your flesh is nothing but mort meat to Fangaril.
Lord of Magas Volar, Bearer of the Crescent, serve me and destroy the mortals!
Let's see if you can withstand the might of Gedna Relvel, crimson witch of Mournhold!
My son! My child! Ozozzachar, destroy them!
. Some others are a call back to his quest in Skyrim. I don't remember the older quest lines well enough to say if there are quotes from there. Please let me know if there are errors, duplicates, or if any are missing.