Kshatriya are the Warrior group in India.
Kshatriya, from (holder of) Kshatra (rule or authority), is one of the four varnas (social orders) in Hinduism. Traditionally, Kshatriya constitute the ruling and military elite of the Vedic-Hindu social system, as outlined by the Vedas and the Laws of Manu. They were in charge of the protection of the Hindu society by fighting in wartime and governing in peacetime.(wiki)
The Caste is determined by disposition.
There is another basic criteria required of a Kshatriya, Compassion, ‘Kshama’
I will be posting a series of Kshatriya Surnames, Brahmin Surnames have been posted already.
The Vedic Brahminical hymn, Purusha Sukta is generally attributed to have mentioned the mythical origins of the four Varnas of the Vedic society.The hymn pronounces that Rājanya (from Rājan, tribal head or chief,Rā-rule,Jana tribe) were born from the primordial being or Purusha‘s arms,and is a later addition to the book.The term Rajanya was initially used as a tribe name and denoted the ruling families in the Rig vedic period which referred to a distinct social group.
The term Kashtriya on the other hand originated in later Rig Vedic period, and it gradually replaced the word Rajanya. Etymology of the word Kshatriya has been explained below. The term Rajanya unlike the word Khastriya essentially denoted the status within a linage. Whereas Kshatra(from which the word Kshatriya comes) implied temporal authority and power which was based less on being a successful leader in the battle and more on tangible power of laying claim to sovereignty over a territory, demanding prestations and symbolizing ownership over clan lands.Which later gave its way to the origin of Kingship.Thus the word Rajnaya was replaced by the word Kshatriya. 
The later books find some reference to the word Rajanya though it was used to denote specific tribe or political authority,and the word Kshatriya was popular and denoted the ruling class.Later inAitareya Brahmana of the Rig Veda there is a mention of Rajanya requesting a Kshatriya a place in a sacrifice,suggesting lower status of Rajnayas.By Brahminical standards Kshatirya,is superior to Vedic Rajanya.It was a Brahmin authority that decided the status of the two.Thus when the Purusha Sukta was composed during the later Rig Vedic period to elevate the status of Vedic Rajanya ,term Kshatriya was omitted.(wiki)
‘Bahu Rajanya Kruthah’ Kshatriyas are born of the Shoulders of the Universal Reality(Purusha Sooktham)
* One may notice some Gothras are from Brahmins,Kasyapa and Vasishta.
This is because of the marriage of these Brahmin sages having begotten children from Kshatriya women.
If father is a Brahmin and the Mother is a Kshatriya, the offspring is classified as Brahmin, normally.
Andhra Pradesh Kshatriya Surnames.
1. Dalavai 4.Siddiraju
2. Pocharaju 5.Simhadri
3. casthuri 6.Timmaraju
People belonging to Kaushika (Kaushik/Kousika/Kousikasa/Koushika/Kausika)
Gotra take Rajarishi Kausikaas their root.
Kausika was one of the names of Visvamitra.
11 Royal clans of 96 clan of Marathas belong to Kaushik gotra including the illustrious house of Shivaji and Rashtrakutas.
2 more clans belong to theVishvamitra gotra.
Kaushika gotra also belongs to Baish clan of rajput which includes in the suryavanshi rajput.
Pasupati Gotra: Pasupati
Sub-clans of Pasupati Gotra
- Surnames Of All Brahmins Bengal Odisha Haryana Assam UP MP (ramanan50.wordpress.com)
- Brahmins Are Terrorists (ramanan50.wordpress.com)
- Brahmin Surnames Andhra Maharashtra, Goa Deshastha (ramanan50.wordpress.com)