diff --git a/decnet/cli/__init__.py b/decnet/cli/__init__.py
index 03461e5a..63de545c 100644
--- a/decnet/cli/__init__.py
+++ b/decnet/cli/__init__.py
@@ -26,6 +26,7 @@ from . import (
     canary,
     db,
     deploy,
+    fleet,
     forwarder,
     geoip,
     init,
@@ -62,7 +63,7 @@ for _mod in (
     swarm,
     deploy, lifecycle, workers, inventory,
     web, profiler, orchestrator, realism, reconciler, sniffer, db,
-    topology, bus, geoip, init, webhook, canary, ttp, supervise,
+    topology, bus, geoip, init, webhook, canary, ttp, supervise, fleet,
 ):
     _mod.register(app)
 
diff --git a/decnet/cli/fleet.py b/decnet/cli/fleet.py
new file mode 100644
index 00000000..3b720719
--- /dev/null
+++ b/decnet/cli/fleet.py
@@ -0,0 +1,94 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""``decnet fleet <name>`` — prefork supervisor (DECNET 1.2).
+
+Imports the shared base floor ONCE in the master, then forks one child process
+per worker (see :mod:`decnet.prefork`). Children share the floor via copy-on-write
+(measured ~71 MB shared / ~1 MB private per idle child on CPython 3.14) while
+keeping their OWN process and GIL — unlike ``decnet supervise``, which co-hosts
+workers as asyncio tasks in one shared-GIL process.
+
+Use ``fleet`` for workers that must stay process-isolated (heavy resident state,
+sustained CPU) but shouldn't each re-import the world; use ``supervise`` for cheap
+co-resident IO workers.
+
+CONSOLIDATION COSTS (same shape as ``supervise``):
+  * Forked children inherit the master's privileges — a fleet's systemd unit
+    carries the UNION of its members' caps. So group by privilege profile, not
+    convenience. The ``heavy`` fleet is DB-only (no docker socket, no raw net).
+  * To share via CoW the master pre-imports each worker's module BEFORE forking,
+    so its RSS is large — but that RSS is the shared floor, not per-child cost.
+"""
+from __future__ import annotations
+
+import typer
+
+from . import utils as _utils
+from .utils import console, log
+
+_FLEETS = ("heavy",)
+
+
+def _build_fleet(name: str) -> dict:
+    """Return ``{worker_name: entry_thunk}`` for *name*.
+
+    Imports happen here, in the MASTER, before :func:`run_fleet` forks — that is
+    what lets children share the imported code/objects via copy-on-write. Each
+    thunk blocks running one worker; ``repo`` is initialized inside the child
+    (post-fork) so every child opens its own pool, never a fork-inherited one.
+    """
+    import asyncio
+
+    if name == "heavy":
+        from decnet.profiler import attacker_profile_worker
+        from decnet.ttp.worker import run_ttp_worker_loop
+        from decnet.web.dependencies import repo
+
+        # Importing the worker modules here (in the master) is what lets children
+        # share their code via CoW. Heavy per-worker runtime state (ATT&CK bundle,
+        # ML) still loads lazily in each child — warming it in the master to share
+        # it too is a future optimization, gated on a live RSS measurement showing
+        # the big object graph actually CoW-shares rather than refcount-dirtying.
+        def _profiler() -> None:
+            async def _go() -> None:
+                await repo.initialize()
+                await attacker_profile_worker(repo, interval=60)
+            asyncio.run(_go())
+
+        def _ttp() -> None:
+            async def _go() -> None:
+                await repo.initialize()
+                await run_ttp_worker_loop(repo, poll_interval_secs=60.0)
+            asyncio.run(_go())
+
+        return {"profiler": _profiler, "ttp": _ttp}
+
+    raise ValueError(f"unknown fleet: {name}")
+
+
+def register(app: typer.Typer) -> None:
+    @app.command(name="fleet")
+    def fleet_cmd(
+        name: str = typer.Argument(
+            ..., help=f"Worker fleet to fork. One of: {', '.join(_FLEETS)}"
+        ),
+        daemon: bool = typer.Option(
+            False, "--daemon", "-d", help="Detach to background as a daemon process"
+        ),
+    ) -> None:
+        """Prefork a worker fleet: shared base floor (CoW), one child process per worker."""
+        from decnet.prefork import run_fleet
+
+        if name not in _FLEETS:
+            console.print(
+                f"[red]unknown fleet {name!r}; known fleets: {', '.join(_FLEETS)}[/]"
+            )
+            raise typer.Exit(2)
+
+        if daemon:
+            log.info("fleet %s daemonizing", name)
+            _utils._daemonize()
+
+        log.info("fleet %s starting", name)
+        console.print(f"[bold cyan]Fleet starting[/] {name} (prefork)")
+        specs = _build_fleet(name)
+        run_fleet(specs)
diff --git a/deploy/decnet-fleet-heavy.service.j2 b/deploy/decnet-fleet-heavy.service.j2
new file mode 100644
index 00000000..607f65a5
--- /dev/null
+++ b/deploy/decnet-fleet-heavy.service.j2
@@ -0,0 +1,48 @@
+[Unit]
+Description=DECNET Heavy Fleet (prefork master forking profiler + ttp as CoW-sharing children)
+Documentation=https://git.resacachile.cl/anti/DECNET/wiki/Workers#fleet
+After=network-online.target decnet-bus.service
+Wants=network-online.target decnet-bus.service
+# Replaces the individual decnet-profiler / decnet-ttp units. Do NOT enable
+# those alongside this one.
+Conflicts=decnet-profiler.service decnet-ttp.service
+
+[Service]
+Type=simple
+User={{ user }}
+Group={{ group }}
+WorkingDirectory={{ install_dir }}
+EnvironmentFile=-{{ install_dir }}/.env.local
+Environment=DECNET_SYSTEM_LOGS=/var/log/decnet/decnet.fleet-heavy.log
+ExecStart={{ venv_dir }}/bin/decnet fleet heavy
+StandardOutput=append:/var/log/decnet/decnet.fleet-heavy.log
+StandardError=append:/var/log/decnet/decnet.fleet-heavy.log
+
+# Prefork master imports the shared base floor once, then forks one child per
+# worker; children share the floor via copy-on-write. Both members are DB-only
+# (no docker socket, no raw sockets) so this unit carries NO extra privilege —
+# the prefork privilege-union cost is nil for this fleet by construction.
+CapabilityBoundingSet=
+AmbientCapabilities=
+
+# Security Hardening
+NoNewPrivileges=yes
+ProtectSystem=full
+# Dev installs under /home need ProtectHome=read-only: the ttp child reads
+# ./rules/ttp/ from the project root (read-only suffices — YAML reads only).
+ProtectHome=read-only
+PrivateTmp=yes
+ProtectKernelTunables=yes
+ProtectKernelModules=yes
+ProtectControlGroups=yes
+RestrictSUIDSGID=yes
+LockPersonality=yes
+ReadWritePaths={{ install_dir }} /var/log/decnet
+
+Restart=on-failure
+RestartSec=5
+# Master forwards SIGTERM to children and reaps; give it room for both to drain.
+TimeoutStopSec=25
+
+[Install]
+WantedBy=multi-user.target
diff --git a/tests/cli/test_fleet.py b/tests/cli/test_fleet.py
new file mode 100644
index 00000000..baadf85b
--- /dev/null
+++ b/tests/cli/test_fleet.py
@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+"""CLI surface for ``decnet fleet`` (DECNET 1.2 prefork). The fork/restart
+mechanism itself is covered by tests/test_prefork.py."""
+from __future__ import annotations
+
+from typer.testing import CliRunner
+
+from decnet.cli import app
+from decnet.cli.fleet import _FLEETS, _build_fleet
+
+runner = CliRunner()
+
+
+def test_fleet_is_registered():
+    result = runner.invoke(app, ["fleet", "--help"])
+    assert result.exit_code == 0
+    assert "fleet" in result.stdout.lower()
+
+
+def test_unknown_fleet_exits_2():
+    result = runner.invoke(app, ["fleet", "not-a-fleet"])
+    assert result.exit_code == 2
+    assert "unknown fleet" in result.stdout
+
+
+def test_heavy_fleet_builds_expected_workers():
+    # _build_fleet imports worker modules + builds thunks but runs nothing
+    # (no fork, no repo.initialize) — safe to call in-process.
+    specs = _build_fleet("heavy")
+    assert set(specs) == {"profiler", "ttp"}
+    assert all(callable(t) for t in specs.values())
+
+
+def test_heavy_is_known():
+    assert "heavy" in _FLEETS