Q: Is there a way to control the number of axes the radar chart has? Can I choose the color of the background?

A: The number of axes depends on the MinValue, MaxValue and Interval properties. Here we make a radar chart with 5 axes:

 radarChart1.MaxValue = 50;
 radarChart1.Interval = 10;
 radarChart1.MinValue = 0;

The color is set with the SecionBrushes and SectionStrokes properties. If the count of brushes in any of those arrays is less than the count of segments to fill, the control cycles through them:

 
 radarChart1.SectionBrushes.Add(Brushes.Gray);
 radarChart1.SectionBrushes.Add(Brushes.LightGray);

 radarChart1.SectionStrokes.Add(Brushes.White);
 radarChart1.OuterAxisStroke = Brushes.White;

Here we fill the background with gray and light gray concentric circles. The border between two adjacent circles is white. The outer axis – the biggest circle is also white.