Submarines
Overview
Submarines are the key to RELL Seas' deepest content. While surface ships rule the open ocean, the true treasures of the world lie in the deep - hidden caves, underwater dungeons, rare sea creatures, and sea regions inaccessible any other way. The submarine is not just a vehicle; it's a progression gate that opens up an entirely different layer of the game.
How to Obtain - Sub Cola
Submarines are summoned using the Sub Cola - a Coca-Cola bottle styled item in the classic One Piece fashion. Drink the bottle, the cap pops open, and the submarine shoots out and grows to full size. You do not start with the Sub Cola - it is unlocked through the progression system.
🎮Controls
When not in battle, the submarine moves smoothly through the water.
Battle Mode changes the submarine's control scheme for combat.
🌊Depth Layers
The ocean is divided into 7 confirmed depth layers. Each layer has unique characteristics, wildlife, currents, and lighting. The deeper you go, the darker, colder, and more dangerous the environment becomes.
Shallow coastal waters. Standard visibility, mild currents, common sea creatures. Accessible without equipment.
Open ocean mid-depth. Visibility begins to reduce. Stronger currents. Sea beasts may appear.
Danger threshold. Without submarine armor, HP drain begins. Wildlife transitions to more aggressive species. Currents intensify.
Deep water. Full darkness without submarine lighting. Piranha-type fish replace surface fish species. Giant fish transition to whale and eel variants.
Extreme depth. Very fast HP drain without submarine armor. Hidden cave entrances found here.
Near-crushing pressure. Instant hazard to unprotected players. Rare dungeon entrances accessible.
Maximum depth. Completely dark. Without a fully-equipped submarine and armor, death is near-instant. The rarest content in the game exists here.
⚠️Pressure System
Pressure is the primary environmental threat in deep-sea exploration. As you descend, the water pressure increases. Without the proper submarine armor equipped, your character begins taking damage on a timed interval - and the deeper you go, the faster that interval ticks.
- ▸Depth 1-2: No pressure damage. Safe for unprotected players.
- ▸Depth 3+: Pressure damage begins. HP drains on a regular interval.
- ▸Depth 6+: Pressure damage is near-fatal for unprotected players.
- ▸Depth 7: Without submarine armor, death is nearly instant.
- ▸Submarine Armor: Fully counters pressure at all depths. All armor pieces must be equipped - partial sets are not sufficient.
Critical Warning
Submarine Armor must be a complete set. Wearing only some pieces does NOT protect you from pressure. This is a hard requirement for deep-sea exploration.
🌀Water Currents
Every depth level has its own directional current. These currents are inspired by One Piece's Grand Line - the real lore features one giant ocean current that influences all sea travel. RELL Seas gives each depth its own current to reward navigation knowledge.
Navigation
The submarine's UI compass changes direction based on the active current. Bubbles rushing in a direction indicate the current flow for that depth.
Hidden Paths
Some currents lead to hidden cave entrances. Following a current to its source may reveal an underwater dungeon, a mini-boss encounter, or a full boss fight with unique rewards.
🐟Underwater Wildlife
Wildlife changes dramatically as you descend. The familiar fish and sea creatures of the surface are replaced by more dangerous deep-sea variants.
- ▸Surface fish (standard species) → Piranha-type fish at depth 4+
- ▸Giant surface fish → Whales and Eels at depth 4+
- ▸Standard sea creatures → Aggressive apex predators at depth 6+
- ▸Leviathans: the largest and most dangerous creatures, found in the deepest depths
🗝️Underwater Content
The underwater world is not just a hazard - it is packed with content accessible nowhere else. Hidden caves discovered through water currents may contain dungeons with mini-bosses or full bosses at their deepest points.
Oxygen System
Players do not have a fixed oxygen timer that counts down to death. Instead, oxygen bubbles spawn randomly around the player as they swim. The deeper you go, the rarer these bubbles become - meaning extended exploration at great depths becomes genuinely dangerous.
💧 Oxygen bubble collectibles spawn around the player during underwater exploration. Collect them to replenish your oxygen.
⚡ Speed boost items also spawn randomly during extended swimming sessions. These help players cover distances without manually pressing forward.
Underwater Physics
- ▸Walk speed is reduced while swimming/moving underwater
- ▸M1 attack animations remain the same speed as on land - combat parity is maintained
- ▸Dashing becomes directional when looking up or down - you move toward your camera angle
- ▸Animations have a slow, floaty quality that adds to the underwater atmosphere
- ▸All sound effects gain a distorted underwater filter
Notes
- ▸Submarines were showcased in Movie 2 and Movie 3 of the RELL Seas developer showcase series.
- ▸The Sub Cola item is a direct One Piece reference - the cola-powered submarine from the Franky arc.
- ▸Submarine armor must be a COMPLETE set - confirmed directly in Movie 3. Partial sets provide no pressure protection.
- ▸Water currents per depth were designed to mirror the Grand Line ocean current concept from One Piece.
- ▸Leviathan battles are a confirmed submarine combat scenario - giant sea creatures exclusive to submarine encounters.
- ▸Sound effects underwater use a distorted filter - the developers went 'all out' on underwater audio design.
- ▸Titanium armor is the confirmed submarine armor material, though full upgrade details are pending.