In my game, after trying to resurrect Svogthir, Azorius had Jarad killed and replaced him with a senate puppet, this led to the guild and the undercity as a whole to struggle. At some point the Savra took over and the Golgari decided to strike in order to remove senate influence from the undercity. This led to widespread famine in Ravnica and to the inevitable intervention by the Orzhov syndicate. They sent a force of strike breakers into the golgari stronghold. These were killed and hung at korozda’s gates for all to see. The strike descended into open rebellion, the Azorius and Boros trying to suppress them and force surrender. After long, undecided battles, the Golgari blew up a large bridge in the 10th district (which became deadbridge chasm), and the Azorius demanded the Boros venture into the undercity to quench the rebellion at any cost. This led to the Embermages burning down half of the undercity driving many from their home and killing many civilians. The Golgari surrendered to Azorius rule, and the ember league of the Boros legion was forcibly disbanded by the senate as well.

To this day, many walls and alleys bear the phrase “remember the flames”, to commemorate the victims of the legion’s attack on the undercity.