Angels of Vengeance
The Angels of Vengeance are a successor Chapter of the Dark Angels, divided from their parent legion during the Second Founding.
Apart from their First and Second Companies being identical to the Dark Angels, there is nothing else to set them apart.
Whoops.
Probably because the pre-Heresy era Legio I (Dark Angels) was already organized into distinct Chapters that each had the same mold and style. As such, the Dark Angels and their successor chapters still operate the same way they did during the Great Crusade. Just with an obsession with secrets. Does this count as trolling Guilliman? It should.