I don't understand your lighting situation, why that over saturated neon green? it doesn't help your color pallet at all. There are also some big anatomical mistakes, the hands on the ninja guy are way too big and the head and hands of the knight are way too small. If he was a monster than things like that can be excused but since he's not then it makes him look really awkward. The lighting situation on the armor is crazy, so far I can see you have 3 light sources, that weird background green, top left corner and top right corner, since they are not in a building with lights on the roof it doesn't make sense why there would be so many light sources in a forest. My best advice is that you should question your decisions. like for example "Where is the light coming from" , "What time of day is it", "How many light sources am I going to use", " Do my color choices make sense?" things like that. Also it wouldn't hurt to double check your anatomy.
The neck of the knight is to large, he looks to strong ^^. And I'm surprised there's no light on the sword. And the trees are a bit repetitive. Why did the ninja have only 4 fingers. Little problems but it still is good.