Rules complexity: High
Strategic depth: High
Warhammer: The Horus Heresy
Warhammer 40,000 is closing out the Horus Heresy story after 17 years, kind of
Sixty-ish books, one huge betrayal.
Warhammer: The Horus Heresy - Age of Darkness review - a perfect introduction to the 40K spin-off
Horus-h to find it.