We have three worlds (lokas) and three ganas as follows:
Swarga Loka (Heaven) - domain of the gods = deva
Prithvi Loka (Earth) - domain of the humans = manusya
Mrityu [Narakha] Loka (Hell) - domain of the demons = Rakshasa
3 groups = "Ganas" which correspond to the predominant energy of one of the 3 lokas, or psychic "worlds".
****"Gana"-psychic character/psychic inheritance and levels of communication between the native and one's ancestors.
*****Still a valid Measurement of compatibility-Astakoot /Guna Milap (6 points out of 36)
*****Describes the accumulation of inherited disposition in the native's psychic field, which derives from the character of the Ancestral spirits with whom we have our relationship (largely unconscious one),and have continuing and directive.
You can find more info on this on http://barbarapijan.com/
Rakshasa (demon) nakshatras are Krittika, Ashlesha, Magha, Chitra, Vishakha, Jyestha, Mula, Dhanistha, Shatabhishak.
People who have rakshas Gana as their birth Gana may have a stubborn and rigid character. They act according to their will which sometimes may not be a good decision. They have a hefty body and may be quite aggressive.
They may have a tendency to fight over small issues. These may also sound harsh and may not be able to realize the impact that their words and actions have on the others. It is found that people of Rakshas Gana are prone to diabeties..
People who have many planets in demon Nakshatras maybe more harsh than those who have planets in the godly nakshatras which are mostly soft. However devas are not necessarily good (heroes)
and demons are not necessarily bad (villans) 
.In fact they both have their role in creation to play and are equally important. If there were no demons, it would be impossible to deal with our karmic problems. In that case, we would probably be playing harp all-day and enjoying the sunshine. Not much spiritual growth would result out of that.
Having said that We cant judge alone on the Gana-the traits are altered and differ based on the rashis,aspects etc.
The 27 Nakshatras have various classifications to alter the characteristics of the native.
***The relationship to the soul (seen in navamsa)- info about the state of the soul and thus of the inner life of the person)padas give info about the soul of a person.
****The gunas, which represents qualities of energy. (Rajas,Tamas,Satva)
****The four purposes of life-which aims of life are stressed in the life of a person ( Dharma,Artha,Kama,Moksha)
In addition to a planet, deity, symbol, aim of life and guna each Nakshatra also corresponds with a certain animal, animal type, caste, sex, temperament, dosha, tattva (element) and even wind direction that can give you clues about how the even a rakshasa gana person will be.
Now think why hitler was a Manusya Gana and Not a Rakshasa Gana???
