Nexus, the last planet of Nexus Extended Promethium Endgame, is still transmitting, and nine things on it answer the signal.

Nothing attacks Nexus on its own: no nests, no random raids. You build a summon beacon, choose the ground, raise the defences you think you need, and light it. Then something comes.

How it plays

Craft a beacon on Nexus and light it. While the countdown runs, the boss's precursors come for the beacon from the side the boss will take, so you see trouble coming. Hold the beacon, kill what arrives and take its trophy.

The signal grows in three stages, each with three bosses. Beat a stage and the next one opens. One trophy from every boss makes the warp key, and the key brings Silence: the signal stops, and the routes of the warp drive open.

• Whisper: the Arachnid Queen, the Watcher, a Rogue Spidertron.
• Chorus: the Twin Maws, a Colossus, the Plague Hulk.
• Convergence: the Storm Guardian, the Devourer, the Last Commander.

The game tells you who is coming, and nothing more.

Between the fights

Someone answered the signal before you. The expedition of the Long Echo broke up on Nexus, and what it left is scattered across the planet.

• The logs. A wreck of the expedition lies out there for every boss, and only its log tells how that boss fights. A signal detector points the way, and every victory reveals another wreck. You can fight blind, but you probably shouldn't.
• The lairs. Every boss has a lair far from your base. Set up direction finders, wait for their bearings to narrow, and where two of them cross you find it. Call a boss in its own lair and it pays better: a second trophy, better each time, and loot. Every lair holds a dead pylon; wake it with a fine enough trophy and the boss comes weaker.
• The storms. When a storm of Nexus Threat breaks, the old lightning ruins near you wake up. Walk into the lightning to pick up a charged shard. The Storm Guardian feeds on storms, and the shards take some of that storm away from it.
• The story. The expedition's camp shows up when the Whisper starts. Where its commander went is something you only learn after Silence, and what he found there is locked behind the glyphs of its builders.

The signal also gets into your head. At night, far from your base, you may see and hear things that are not there, more often the deeper you go. A player setting turns it down or off.

Rewards

• A trophy from every boss, every time.
• Each finished stage sharpens the weapons the next one needs.
• The Storm Guardian's death leaves the storms of Nexus weaker for good.
• Silence opens the routes of the warp drive.

Every trial has its own sounds and fight music, and the technologies carry one emblem of the signal in four states. Nexus itself plays FIELDS from TFMG: Music.

Good to know

• Nexus has no ordinary nests or worms: its enemies come only from the beacons. Added to a running game, the mod clears the enemies already there.
• One trial at a time on the whole server.
• The bosses of Big Monsters need explored land around your spawn. If there is none, the beacon comes back with a message.
• Settings: boss health, beacon cost, countdown length, whether the trials gate the warp drive, and whether Big Monsters' bosses come only from the beacons.
• Silence opens the Oort cloud and Sol. The edge of the system and the shattered planet open by their own technologies, as without this mod. The gate can be turned off in the startup settings.
• Big Monsters' "allow nuker" is off by default with this mod, so the Last Commander's soldiers carry no atomic rockets. You can turn it back on.
• Administrators can stop a stuck trial with /nexus-bosses-abort.

Requirements

Nexus Extended Promethium Endgame with Nexus Threat, Big Monsters, Toxic biters, Arachnids enemy and Electric flying enemies: the bosses are built from their creatures. TFMG: Music gives Nexus its music. razi-protocol is optional.

Source and bug reports: GreenTech-Solutions/nexus-bosses. Thanks to MFerrari for Big Monsters and the enemy mods, and to Karu_Kiruna for Nexus. Sounds, music and icons: CREDITS.md.