Yakshas/यक्ष:m. N. of a class of semi-divine beings (attendants of कुबेर , exceptionally also of विष्णु ; described as sons of पुलस्त्य , of पुलह , of कश्यप , of खसा or क्रोधा ; also as produced from the feet of ब्रह्मा ; though generally regarded as beings of a benevolent and inoffensive disposition , like the यक्ष in कालिदास's मेघ-दूत , they are occasionally classed with पिशाचs and other malignant spirits , and sometimes said to cause demoniacal possession
Gandharvas/गान्धर्व: the chief or leader of the गन्धर्वs is named चित्र-रथ.especial duty is to guard the heavenly सोम,are governed by वरुण (varuna) (just as the आप्सरसs are governed by सोम (soma)supposed to be a good physician , because the सोम is considered as the best medicine ; possibly , however , the word सोम originally denoted not the beverage so called , but the moon , and the heavenly गन्धर्व may have been the genius or tutelary deity of the moon
Apsara/Apsarasa/अप्सर्/आप्सरस: the wives of the Gandharvas are the Apsarasas. आस् ([ RV. AV. &c ]) , or अप्-सर्/आ ([AV. &c ]) , f. (fr. 2. /अप् √ सृ) , " going in the waters or between the waters of the clouds " , a class of female divinities (sometimes called " nymphs " ; they inhabit the sky , but often visit the earth ; they are the wives of the गन्धर्वs (q.v.) and have the faculty of changing their shapes at will ; they are fond of the water ; one of their number , रम्भा , is said to have been produced at the churning of the ocean).
Kimnaras/किंनर:m. " what sort of man? " a mythical being with a human figure and the head of a horse (or with a horse's body and the head of a man S3is3. iv , 38 ; originally perhaps a kind of monkey cf. वा-नर ; in later times (like the नरs) reckoned among the गन्धर्वs or celestial choristers , and celebrated as musicians ; also attached to the service of कुबेर
Note: The Kimnara's have part animal forms, Which is not the description given to Gandharvas or Apasaras
Rakshasa/राक्षस: m. a रक्षस् or demon in general , an evil or malignant demon (the राक्षसs are sometimes regarded as produced from ब्रह्मा's (brahma's)foot , sometimes with रावण as descendants of पुलस्त्य , elsewhere they are styled children of खसा or सु-रस ; according to some they are distinguishable into 3 classes , one being of a semi-divine benevolent nature and ranking with यक्षs &c ; another corresponding to Titans or relentless enemies of the gods ; and a third answering more to nocturnal demons , imps , fiends , goblins , going about at night , haunting cemeteries , disturbing sacrifices and even devouring human beings ; this last class is the one most commonly mentioned
Note: Many consider Rakshasa as evil, But they are also benevolent, Example being When Sun god sends a Rakshasa to protect Draupadi when she was forced to go to Kichaka's house. Raakshasas can also be a strong protective force.