I have no idea about Makinom, but for ORK, if you wanted to only use what was possible out of the box without any scripting, you could look at conditional prefabs to handle. Basically you would have a different prefab of each main color, and switch them out based on the HP remaining on the combatant (cube in your case). You wouldn't have a smooth transition of color however. There might be another way, but I'm not sure off the top of my head.
If you wanted to make a super tiny script, you could easily do what you want in ORK and have a smooth color transition. Basically, your script would do something like this from unity's documentation (http://docs.unity3d.com/ScriptReference/Material-color.html). But for perf reasons, I wouldn't put your change stuff in an Update function, I'd instead do a custom function all that just changes the color by a set RGB value (like adding <0,5,5> with every hit), and call that function from an event node in your damage calculation in ORK.