The Scar Engine is a game engine developed by NINE100 Studios, designed to be easily used in a large variety of games in both 2D and 3D perspectives. The idea of a new engine was originally conceived when the developers of In Decay found that Unreal Engine 4 didn't offer all of the features they wanted, and as such decided to create their own engine for use in many different projects. it has since become a staple of many NINE100 Studios' games.
The idea of the Scar Engine was first suggested during the pre-production stages of In Decay, when the developers felt that Unreal Engine 4 didn't offer all the capabilities they wanted from a game engine. The team eventually decided to hold off working on In Decay for a short while the engine was designed, developed and tested. When a fully working initial prototype was created, the developers worked on a segment of In Decay using the engine to see how it works. The developers found that the initial version of the engine was very successful, and thus the prototype became the first official version of the engine, known as Scar v1.