By Ramesh Gopalakrishnan
BBC Tamil service
The 40-year-old Tamil Tiger commander Colonel Karuna was once a bodyguard of his chief, Velupillai Prabhakaran, but now he is facing the leadership's wrath.
Karuna fought key battles in the north
Karuna in Tamil means kindness, but the colonel is a hardened strategist commanding the loyalty of a substantial number of cadres, now ensconced in Kokkadicholai, a rebel pocket off Batticaloa in the east.
Colonel Karuna is the nom de guerre of Vinayagamoorthi Muralitharan. He joined the militant outfit in 1983 and, within a few years, became the top commander in his native eastern province.
However his key achievements were to come later in the north, in the Tamil Tigers' battles against Sri Lankan security forces.
Colonel Karuna is said to have been the strategist behind the Jayanthan Force, which helped the Tigers' successful resistance of the Sri Lankan army's Operation Jayasikuru in 1997-98.
The operation against the north was beaten back and the Tigers subsequently captured the strategic Elephant Pass, allowing them to negotiate from a position of strength.
Of that bloody campaign, he says: "As a soldier who has participated in so many wars I have no fear about death. Death means nothing to me compared with the rights of our people."
Banner of revolt
Colonel Karuna's importance in the Tamil Tiger hierarchy became clear when rebel leader Velupillai Prabhakaran elevated him to the rank of special commander for the eastern Batticoloa-Amparai districts in 2003.
He replaced special commander Karikalan, who was ousted following his remarks over the communal situation in the district.
Prabhakaran later made Colonel Karuna part of the team that negotiated with the Sri Lankan government during several rounds of peace talks in Bangkok, Oslo and Tokyo.
During these rounds, Colonel Karuna, who initially seemed reticent in his interactions with journalists, came out as an articulate man with lucid views on the issues confronting the east.
He felt his personal promotion was not enough for the east and has been seeking better representation for eastern cadres within the Tamil Tiger hierarchy.
Colonel Karuna is perhaps now trying to restate these feelings but whether his gamble pays off remains to be seen.
By choosing to raise the banner of revolt at this moment, in the run-up to parliamentary elections, Colonel Karuna has certainly sprung a surprise.
The Sri Lankan government has quickly rejected his demand for a separate ceasefire, but Prabhakaran is taking his time to react to the challenge from his top regional commander.
In the past, the Tamil Tiger guerrilla chief has always acted decisively to ensure his outfit remains predominantly a military one with little space for political dissent.
It remains to be seen whether he will be prepared to take action that breaches the ceasefire with the Sri Lankan armed forces.
But when Prabhakaran does decide to act, Colonel Karuna might face the toughest battle of his life.