In which caste was Lord Krishna born into?
There are verses in "Shreemad Bhagvatam" that points towards "Lord Shree Krishna's" relation with Pandavas. Although he has been raised in Gokula, Kunti mother of Pandavas was sister of Vasudeva (Father of shree Krishna"). So we can say that Shree krishna was a kshatriya.
तं मातुलेयं परिरभ्य निवृतो भीम: स्ययन प्रेमजवाकुलेइंद्रिय:।
यमौ किरीटी च सुह्यत्तमं मुदा प्रवृद्धबाष्पा: परिरेभिरेsच्युतम।।27।।
Tam Matuleyam Paribhya Nivritto Bhimah Sasyan Pramjava kule indriya Yamo kiriti Ch Suhruttmam Muda Pravrubgdbashpah Paribhirechhutam.
Meaning - Then Bheema smiled and hugged his "Maternal Cousin Shree krishna" Nakula ,Sahadeva and Arjuna also hugged Shree Krishna and their eyes filled with tears from the great love towards Shree Krishna.
In that chapter there is also a Verse of conversation between "Uddhava" and Shree Krishna.Where Uddhava is telling Shree krishna to help His "Paternal Cousins" pandavas.
यदुक्तमृषिणा देव साचिव्यं यक्ष्यतस्यत्वया ।
कार्यम पैतृषयव सेयस्य रक्षा च शरणैषिणाम् ।।2।।
Yadukatamrushina Dev Sachivyam Yakshyatastvaya Karyam Paitushvaseyasya Raksha ch Sahranaishinaam
Meaning - Bhagvan , as told by "Devarshi Narada" you should help your "Paternal Cousins" in their Yagna. Also its a duty of you to help those who surrender to you.
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