Cephlonians:

A race of cephalopods. Cephlonians have eight arms and two tentacles. The Cephlonians are aquatic creatures. Cephlonians are capable of great acts of strength and stealth.

Ability Score Increase:

+2 STR

Alignment: Cephlonians are solitary creatures. They have no particular alignment.

Age: Cephlonians are mature by age 8. Cephlonians can live up to 32, or twice as long with modern medical technology.

Size: Sizes vary wildly in Cephlonians. You are medium or small.

Speed: 25 feet walk speed. 50 feet swim speed.

Camouflage: You have advantage on stealth checks while underwater.

Gripping: You have advantage on Athletics checks made to grapple while underwater.

Deep Vision: You can see 120 feet underwater, even in darkness.

Amphibious: You breathe air and water.

Depths Resistance: You are used to the cold depths. You resist cold and bludgeoning damage.

Radiation sensitivity: You have spent your life under the ice with no stars. You are vulnerable to radiant damage.

Languages: You can understand and 'speak' Cephlonian. It is a language spoken using patterns on the skin.

seems good, do they have a space program?

Not yet. They first have an ice drilling program, and once you are past the ice it is relatively easy to escape. Water isn't as dense as rock, so the gravity is lower, and there atmosphere is frozen. They could get into space in a few hundred years, or sooner if they can obtain alien technology.

how detectable is their activity from the outside?

Quote from blackcat31102 >>

how detectable is their activity from the outside?

 Not at all. They are trapped under the ice. If it thaws or they drill out, only space centers will be visible. Water is very good at blocking radiation.

sonar?

Sonar goes right through ice, if someone were to land on the planet and use Sonar on the ice, they could hear signs of life below the ice.

*ok*

do they have any lineage feats?

Not now, maybe later. If there will be one, it will almost certainly be water or camouflage based.

ok. ill get started on making an explorer.

rolling ability scores:14 14 17 11 18 14

hit points:40

*done!*

a ship lands on the surface of cephlos 555. some of the cephalonians' sensors will feel the impact through the ice.

*Sorry for the late reply.*

Meanwhile, in outpost 8742...

"Sir. The seismographs detected an impact."

"So? It happens all the time."

*Context: Meteors exist.*

"According to our tests, the frequency is unlike any we have heard before. It's not iron, and it's not rock, something harder than anything we have made, and it's shape is much like our submersibles. We should drill up to see what it is."

"Are you insane? We agreed not to drill to the surface. Our active SONAR shows there is nothing up there, no water, nothing."

"That's why we made the water lock. Drill some, add a water lock. Repeat."

"Who knows if it will work? Also, the surface is constantly bombarded. Why should we do it for a oddly shaped chunk of metal?"

"It could be a person up there. What if another nation already drilled up? What if there is another ocean out there?"

*They have no concept of anything above the ice, except for the noises of impacts. The current widely accepted theory is that rock and iron spontaneously appears in the void, creating the impact sound.*

they sense a whirring sound, like a drill

They are now certain someone is alive up there, and begin to drill up, leaving 'water locks' along the way.

as they get further up, the ice becomes warmer, and they see a faint glow

They continue.

eventually, they reach pockets where the ice has melted