Spoilers

This is a DOS2 fight.

You either want to get up in the rafters and blow the smokepowder up from a safe distance or you want to make a surface that benefits you. There are water barrels in the adjoining room that you can position to protect yourself from the firewine surface the explosion creates.

The cheese way to do it is sneak into the room, get all the barrels and put them around bosses and then blow them up from a safe distance.