Evil is a symptom if disease. Goodness is a symptom of health.
And because Lightworkers and Darkworkers alike can be diseased or healthy, both Lightworkers and Darkworkers can be evil, and both Lightworkers and Darkworkers can be good.
A diseased Lightworker will have the illusion that they are helping others, and a diseased Darkworker will have the illusion that they are helping themselves. A healthy Lightworker will actually be helping others and a healthy Darkworker will actually be helping themselves.
And, what's interesting is that we all go through waves of being Lightworkers (focusing on others' health and happiness) and Darkworkers (focusing on our own health and happiness) as we go through life. Though people have different wavelengths and frequencies, so sometimes it seems as if someone will be at one end or another for a long time.
For more info about these wave patterns of our life, take a look at the
Spiral Growth theory (starring the ever so elegant Nautilus shell, and with a special guest star of the cuttlefish!), which is based on systems theory, biological development, Maslow's Hierarchy of Needs, and Spiral Dynamics/Integral/AQAL theory.
-Turil