Sea Emperor Leviathan

The Sea Emperor Leviathan is an ancient creature in the original Subnautica and one of the most important characters in the game's story. It is the last surviving member of its species, held captive by the Architects in the Primary Containment Facility deep below Planet 4546B. The creature is voiced by Lani Minella.

Physical description

The adult Sea Emperor measures approximately 200 meters in length, making it the largest known living creature in the volcanic crater. Its body is stocky and armor-covered, predominantly pale brown with blue-green shading. Its head has two striped antennae with glowing green lures on the snout, two large mandibles on each side of the mouth, and a glowing hollow between the mandibles. Seven long tentacles trail from its posterior. One large central tentacle surrounded by six smaller ones.

Age and captivity

The Sea Emperor is approximately 2,600 years old at the time of the game, far exceeding its species' natural lifespan. Its extreme age contributes to its weakened state and its inability to produce stable Enzyme 42. It has spent centuries alone in the Primary Containment Facility at approximately 1,200 meters depth in the Lava Lakes biome.

Telepathic communication

The Sea Emperor communicates telepathically. Its messages appear as green-tinted text accompanied by screen distortion similar to Warper teleportation effects. The Architects could not hear the Emperor's telepathy. It states: "I asked them for this freedom, but they could not hear me." Only Ryley Robinson can perceive the communications, implying a sensitivity that the Architects lacked.

First contact occurs when the player attempts to disable the Quarantine Enforcement Platform or reaches the Disease Research Facility. The Sea Emperor's first words are simply: "What... are... you?"

Dialogue

The Sea Emperor's dialogue is sparse but memorable. Upon the player entering the Primary Containment Facility:

"Are you here... to play? Others came here once. They built these walls. They played... alone. They bored me. Now they're gone. And instead... we have you. We are curious whether you swim with the current, or fight against it as they did."

When asking for help hatching its eggs:

"My young want to hatch. To play outside this place. We have been here so long. The others built a passage to reach the world outside. I asked them for this freedom, but they could not hear me. If you help us, I will give you freely what the others tried in vain to take."

Its final words before dying:

"What is a wave without the ocean? A beginning without an end? They are different, but they go together. Now you go among the stars, and I fall among the sand. We are different. But we go... together."

Enzyme 42 and the hatching

The Sea Emperor naturally produces Enzyme 42, the only known cure for the Kharaa bacterium. The adult's enzyme was too unstable to synthesize at scale. Five eggs in the facility's aquarium hold the key.

Ryley crafts hatching enzymes from five ingredients: Eye Stalk, Ghost Weed, Fungal Sample, Bulb Bush Sample, and a Sea Crown from the aquarium's trenches. The first four are gathered through the facility's Alien Arch teleporters leading to the Lost River Ghost Forest, Crag Field, Mushroom Forest, and Bulb Zone.

All five eggs hatch. The juveniles measure approximately 90 meters. Unlike their parent, they produce stable Enzyme 42. They immediately release massive quantities into the water, curing Ryley and every infected organism on the planet, then depart through the Alien Arch near the Quarantine Enforcement Platform.

Death

Shortly after its offspring hatch, the adult plays with them briefly, then dies of old age. It releases the last of its Enzyme 42 as small orange floating globules that cure the player on contact. The moment is widely considered one of the most emotionally affecting scenes in the game.