You can take a bus from Bengaluru to Kallakurichi via Chennai in around 13 h.
How to get from Bengaluru to Kallakurichi
From Bangalore bus to Chennai then bus to Kallakurichi. 13 h ₹1,316. From Mantri Square Sampige Road Metro to Yesvantpur Junction (YPR), night train to Chinna Salem (CHSM), then taxi to Kallakurichi. 7 h 28 min ₹1,539. From Bengaluru taxi to Kallakurichi. 3 h 51 min ₹5,269. From Bengaluru drive to Kallakurichi. 3 h 51 min ₹1,981.