Sinner's Row is the location of a mission in Azure Striker Gunvolt, codenamed "Kaleidoscope". Gunvolt must chase down Zonda, a dangerous adept of Sumeragi's that has slipped inside after defeating Zeno.
Moniqa: Sorry for pinging you in the middle of the night... Your target has fled into the sketchy side of a town nearby. You can thank the said target for taking Zeno out of the game. Proceed with extreme caution...
This stage's gameplay at the start will be very simple. There will be tons of Launchers and Gunners as you walk through the stage. It will require a lot of jumping since you will eventually find "holes" in the stage, there will also be some commercials in the stage that act as platforms. A new bomber will appear and you need to use the Flashfield from dodge their attacks but its health is quite low.
After some time you will find an Hexapyle wall, destroy it and a cutscene will happen where Zonda will appear to talk with you. Just skip the cutscene or read it and you will enter in the next area, This area will be pretty similar from the one you saw earlier but with more Fire Gunners and the Ice Robot from Merak's stage. You will also find more Medals in this area and there will be points you will need to use Flashfield to go. There are also mirrors made by Zonda's septima that act as portals
A new area will appear with random characteristics, you will need to find another mirror until you find the real one to bring you to the Boss (Copen). Try to examine that wall before going deeper or else you might enter in a Enemy Trap and you will need to fight random enemies in order to go.
One of the mirrors you enter will invert the stage, turning it upside down.
In the Stage's ending, you will find Zonda killed by a mysterious person who will be your opponent. He will mainly use weapons based on the specific bosses you've defeated so far. He doesn't use his Special Skill and is the only boss that is not a member of Sumeragi or an Adept.