There would need to be an invading force to the plane so that you can keep the flavor of magic. Although invasion and scars have done this previously, the plane being invaded was not against violence. I think this set would have to feel white in nature. White is all about preventing damage, and exiling things instead of killing them. The following are some ideas to portray pacifistic elements into a set:
Defender being a recurring theme. This has been done before in rise of the eldrazi, so doing it again there would need to be something different this time around.
Prevention effects. Preventing damage to creatures or players is a mechanic that comes up often, but it is usually not a major theme.
[[Magic: East West Draft Cast Custom Set/Flavor Discussion | Flavor Discussion]]