diff --git a/alembic/versions/0009_fc2d_iii_post_attachment.py b/alembic/versions/0009_fc2d_iii_post_attachment.py
new file mode 100644
index 0000000..4820fa4
--- /dev/null
+++ b/alembic/versions/0009_fc2d_iii_post_attachment.py
@@ -0,0 +1,68 @@
+"""fc2d-iii: post_attachment + import_batch.attachments
+
+Revision ID: 0009
+Revises: 0008
+Create Date: 2026-05-19
+
+Internal forward-correctness migration (big legacy-import migration
+stays deferred). No backfill — no attachments exist yet.
+"""
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+
+revision: str = "0009"
+down_revision: Union[str, None] = "0008"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "post_attachment",
+        sa.Column("id", sa.Integer(), primary_key=True),
+        sa.Column(
+            "post_id", sa.Integer(),
+            sa.ForeignKey("post.id", ondelete="SET NULL"), nullable=True,
+        ),
+        sa.Column(
+            "artist_id", sa.Integer(),
+            sa.ForeignKey("artist.id", ondelete="SET NULL"), nullable=True,
+        ),
+        sa.Column("sha256", sa.String(64), nullable=False),
+        sa.Column("path", sa.Text(), nullable=False),
+        sa.Column("original_filename", sa.Text(), nullable=False),
+        sa.Column("ext", sa.String(32), nullable=False),
+        sa.Column("mime", sa.String(128), nullable=True),
+        sa.Column("size_bytes", sa.BigInteger(), nullable=False),
+        sa.Column(
+            "captured_at", sa.DateTime(timezone=True),
+            server_default=sa.func.now(), nullable=False,
+        ),
+    )
+    op.create_index(
+        "ix_post_attachment_sha256", "post_attachment", ["sha256"],
+        unique=True,
+    )
+    op.create_index(
+        "ix_post_attachment_post_id", "post_attachment", ["post_id"],
+    )
+    op.create_index(
+        "ix_post_attachment_artist_id", "post_attachment", ["artist_id"],
+    )
+    op.add_column(
+        "import_batch",
+        sa.Column(
+            "attachments", sa.Integer(), nullable=False,
+            server_default="0",
+        ),
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("import_batch", "attachments")
+    op.drop_index("ix_post_attachment_artist_id", table_name="post_attachment")
+    op.drop_index("ix_post_attachment_post_id", table_name="post_attachment")
+    op.drop_index("ix_post_attachment_sha256", table_name="post_attachment")
+    op.drop_table("post_attachment")
diff --git a/backend/app/models/__init__.py b/backend/app/models/__init__.py
index db65914..25c2d12 100644
--- a/backend/app/models/__init__.py
+++ b/backend/app/models/__init__.py
@@ -11,6 +11,7 @@ from .import_settings import ImportSettings
 from .import_task import ImportTask
 from .ml_settings import MLSettings
 from .post import Post
+from .post_attachment import PostAttachment
 from .series_page import SeriesPage
 from .source import Source
 from .tag import Tag, TagKind, image_tag
@@ -25,6 +26,7 @@ __all__ = [
     "Source",
     "Credential",
     "Post",
+    "PostAttachment",
     "SeriesPage",
     "ImageRecord",
     "ImageProvenance",
diff --git a/backend/app/models/import_batch.py b/backend/app/models/import_batch.py
index 26003e3..d26db4c 100644
--- a/backend/app/models/import_batch.py
+++ b/backend/app/models/import_batch.py
@@ -25,6 +25,7 @@ class ImportBatch(Base):
     imported: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
     skipped: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
     failed: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    attachments: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
 
     status: Mapped[str] = mapped_column(String(16), nullable=False, default="running", index=True)
     # running | complete | cancelled
diff --git a/backend/app/models/post_attachment.py b/backend/app/models/post_attachment.py
new file mode 100644
index 0000000..4fea125
--- /dev/null
+++ b/backend/app/models/post_attachment.py
@@ -0,0 +1,47 @@
+"""PostAttachment — a non-art file preserved from a post.
+
+Art images become ImageRecords; everything else a post contained
+(archives, .exe, .pdf, ...) is captured here so nothing is lost.
+post_id is nullable (set only when an adjacent sidecar yields a Post);
+artist_id mirrors the canonical attribution model (FC-2d-vii-c). Both
+FKs are SET NULL so deleting a Post/Artist never deletes the preserved
+binary row.
+"""
+
+from datetime import datetime
+
+from sqlalchemy import (
+    BigInteger,
+    DateTime,
+    ForeignKey,
+    Integer,
+    String,
+    Text,
+    func,
+)
+from sqlalchemy.orm import Mapped, mapped_column
+
+from .base import Base
+
+
+class PostAttachment(Base):
+    __tablename__ = "post_attachment"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True)
+    post_id: Mapped[int | None] = mapped_column(
+        ForeignKey("post.id", ondelete="SET NULL"), nullable=True, index=True
+    )
+    artist_id: Mapped[int | None] = mapped_column(
+        ForeignKey("artist.id", ondelete="SET NULL"), nullable=True, index=True
+    )
+    sha256: Mapped[str] = mapped_column(
+        String(64), nullable=False, unique=True, index=True
+    )
+    path: Mapped[str] = mapped_column(Text, nullable=False)
+    original_filename: Mapped[str] = mapped_column(Text, nullable=False)
+    ext: Mapped[str] = mapped_column(String(32), nullable=False)
+    mime: Mapped[str | None] = mapped_column(String(128), nullable=True)
+    size_bytes: Mapped[int] = mapped_column(BigInteger, nullable=False)
+    captured_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), nullable=False, server_default=func.now()
+    )
diff --git a/tests/test_migration_0009.py b/tests/test_migration_0009.py
new file mode 100644
index 0000000..f2a0d1f
--- /dev/null
+++ b/tests/test_migration_0009.py
@@ -0,0 +1,37 @@
+"""FC-2d-iii: post_attachment table + import_batch.attachments column."""
+
+import pytest
+
+from backend.app.models import ImportBatch, PostAttachment
+
+pytestmark = pytest.mark.integration
+
+
+def test_post_attachment_columns():
+    cols = {c.name for c in PostAttachment.__table__.columns}
+    assert {
+        "id", "post_id", "artist_id", "sha256", "path",
+        "original_filename", "ext", "mime", "size_bytes", "captured_at",
+    } <= cols
+
+
+def test_import_batch_has_attachments_counter():
+    assert "attachments" in {c.name for c in ImportBatch.__table__.columns}
+
+
+@pytest.mark.asyncio
+async def test_post_attachment_roundtrip(db):
+    from backend.app.models import Artist
+
+    a = Artist(name="Zed", slug="zed")
+    db.add(a)
+    await db.flush()
+    att = PostAttachment(
+        post_id=None, artist_id=a.id, sha256="z" + "0" * 63,
+        path="/images/attachments/z00/z.zip", original_filename="pack.zip",
+        ext=".zip", mime="application/zip", size_bytes=123,
+    )
+    db.add(att)
+    await db.flush()
+    got = await db.get(PostAttachment, att.id)
+    assert got.original_filename == "pack.zip" and got.post_id is None