Text/Data is from

https://www.youtube.com/watch?v=lEqlG6bhZ80

and

https://fextralife.com/forums/t316456/tribute-does-not-flow-from-a-dead-race/

Mass Effect 3 (Leviathan DLC) – Conversation with Leviathan

(huge alien beast rises from the ocean depths in front of Shepard's dive suit)

You have come too far.

(Shepard starts feeling funky)

Shepard: I had to find you.

This is not your domain. You have breached the darkness.

Shepard: You killed a Reaper. I need to know why.

They are the enemy. One that seeks our extermination.

Shepard: But...I thought you were a Reaper.

They were only echoes. We existed long before.

Shepard: Then what are you?

Something more.

(Shepard suddenly is somewhere else)

Your mind belongs to me.

(Doctor Ann Bryson walks up to Shepard)

Breathe.

Shepard: Ann? What's happening?

Your memories give voice to our words. Your nature will be revealed to us. Accept this.

Shepard: The galaxy's at war with the reapers. You defeated one. Why aren't you fighting back?

There is no war. There is only the harvest.

Shepard: Then help us stop it!

None have the strength in past cycles. Your own species could be destroyed with a single thought. But you are different. I have witnessed your actions in this cycle: the destruction of Sovereign; the fall of the Collectors. The reapers perceive you as a threat.

And I must understand why.

(Shepard starts bleeding from the nose)

Before the cycles, our kind was the apex of life in the galaxy. The less species were in our thrall, serving our needs. We grew more powerful, and they were cared for. But we could not protect them from themselves. Over time, the species built machines that then destroyed them. Tribute does not flow from a dead race.

To solve this problem, we created an intelligence with the mandate to preserve life at any cost. As the Intelligence evolved, it studied the development of civilizations. It's understanding grew until it found a solution.

In that instant it betrayed us.

It chose our kind as the first harvest. From our essence, the first Reaper was created. You call it Harbinger.

Shepard (Intelligence?): You built that machine despite what you saw the other races' experience. Why?

You cannot conceive of a galaxy that bends to your will.

Every creature, every nation, every planet we discovered became our tools. We were above the concerns of lesser species.

The Intelligence was envisioned as simply another tool.

Shepard: And now we all pay the price for your mistake.

There was no mistake. It still serves its purpose.

Shepard: How did you remain hidden all this time?

Our extermination was not complete. Some survived and found refuge in the dark corners of the galaxy. I am their progeny.

Over the cycles the thrall races were controlled, removing traces of our existence as we directed them to.

In this way, our survival was kept secret from the Reapers.

Today, we reach out through the fragments and watch for discovery.

Shepard: Fragments? You mean the artifacts we found?

They provide a window in the galaxy. Tools for exploring the events of this cycle from the safety of this world.

Through them, we watch, we study, and remain in the shadows.

Shepard (The First Harvest): How did the Intelligence defeat you?

To find a solution, it required information – physical data drawn from organic life in the cosmos.

It created an army of pawns that searched the galaxy, gathering this data.

There was no warning, no reason given when they turned against us. Only slaughter.

Only the Harvest.

Shepard (The Reapers): Tell me about the Reapers.

Perfect in its design. Each formed in Harbinger's image. Our image.

Each reaper has the power to influence organics. Over countless cycles, this ability was refined, perfected and gave rise to indoctrination.

Shepard (Why Cycles?): But what's the point of all these harvests?

The Intelligence has one purpose: preservation of life. That purpose has not been fulfilled.

It directed the reapers to create the mass relays - to speed the time between cycles for greatest efficiency.

The galaxy itself became an experiment. Evolution its tool.

Shepard: Will it ever end?

Unknown. Until the Intelligence finds what it is looking for, the harvest will continue.

Shepard (The Crucible): What do you know about the Crucible?

We have watched its construction before. It has never been completed.

Those who have tried still fell victim to the Harvest.

Its outcome is unknown.

Shepard: Okay, you made your point. Will you help stop the cycle?

I have searched your mind. You are an anomaly – yet that is not enough.

Shepard: Wait!

The cycle will continue.

Shepard: No! You have been watching. You know this cycle is different.

We will survive. You will remain here as a servant of our needs. The Reapers will harvest the rest.

Shepard: If you release me, no one has to be harvested.

Leviathan: Nothing will change.

Shepard (Paragon) (It already has): The Reapers know where you are! You can't just watch any more - you have to fight! Even if you survive the battle today, the Reapers won't stop – ever. Release me, and we have a chance to end this once and for all.

Shepard (Renegade) (That's your fault): You are responsible for this! Every race that has ever been destroyed is because of you. And now the reapers will destroy you too. Unless you start fighting. Even if you survive the battle today, the reapers won't stop - ever. Release me, and we have a chance to end this once and for all.

(Shepard is now alone in their mind again)

(Outside, two more Leviathans are rising from the depths)

(The image of Ann Bryson appears again inside Shepard's mind)

Your confidence is singular.

Shepard: I've earned it: out there fighting, where you should be.

It is clear why the Reapers perceive you as a threat. Your victories are more than a product of chance.

We will fight. But not for you, or any lesser race. We were the first, the apex race. We will survive.

And the Reapers who trespass this world will understand our power. They will become our slaves.

Today, they pay their tribute in blood.

(Shepard awakes inside the dive suit and hits the emergency blow and ascends to surface. Once Shepard arrives on the surface, the Leviathans force the Reaper husks to start fighting each other while Shepard and his crew limp off to the waiting shuttle. Once inside the shuttle, Ann Bryson appears on the comm screen)

Ann Bryson: Was it worth it?

Shepard: I don't know, but we proved it can't hide any more... that it's a part of this war, just like us.