( The SH in this name is pronounced like one between 's' in 'sip' and 'sh' in 'ship', N like 'n' in 'no' and D like 'd' in 'do' )
See also the link 'sthoona'.
Shikhandi was the son of the Paanchaala king Drupada. Dhrishtadyumna,Shvetha etc were his younger brothers. Droupadi was his younger sister. Shikhandi's life was an interesting one.
Once king Drupada of Paanchaalam worshipped Lord Shiva with a view to begeting a son that could defeat Bheeshma, as he had some old score to settle with him. At the same time, Kaashi princess Amba, suffered a severe damage (of losing his lover and married life) because of bheeshma. She failed in winning over him, eventhough the great sage Parashuraama himself fought for her but only to lose . She went to hermits to observe penance to acquire power to kill bheeshma. She too was given a boon by Lord shiva that she would first take birth as a girl and then become a man when she would kill Bheeshma. Similarly, he granted a boon to Drupada too that he would have a girl first who later would become a man and kill Bheeshma. Fitting these two boons, Amba in her next birth was born as a daughter to Drupada. Drupada named that girl Shikhandi but he and his queen told everybody that they had got a son. They brought him up claiming that it was a boy. After growing young, his parents married him with daughter of Dashaarna king Hemavarma, maintaining the secrecy. The bride smelt the fraud and sent word to her father about it. Hemavarma turned furious and came to punish Drupada. Shikhandi became sad about the developments and went into the nearby forests to die there by committing suicide. There a yaksha named Sthoonakarna or Sthoona prevented her from suicide and learnt her story. Driven by the destiny, he kindly offered to exchange his masculinety with her so that he could go back home to prove his parents right and return back to exchange his womanship again. That was agreed, Shikhandi went home as a man, saved his parents and returned to the Yaksha. But, meanwhile, the yaksha chief Kubera paid a visit to that place and his servant yaksha in a woman's form felt ashamed to come out to bow to his lord and remained within. Kubera was annoyed with the disobedience and ordered his men to bring him out. The men learnt from the unfortunate fellow what had happened and reported to their master. Kubera was furious over the unauthorised act of his servant and barred him from becoming a man again. After much pleading from the ill-fated servant, he graced that the yaksha was to remain a woman as long as Shikhandi would be alive.
Thus Shikhandi luckily remained a man till his death. But,the curious part of the story is that his turning into a man became a crucial point in the epic. The kourava grandsire Bheeshma had a vow that he wouldn't kill or fight with a woman-turned-man. This self-imposed condition of the old warrior became very useful to the paandavas in the war. They placed Shikhandi opposite Bheeshma who wouldn't fight him and then Arjuna hit Bheeshma from behind Shikhandi's bow. The old stalwart at last fell down.
Thus Shikhandi's accidental benefit in his life played a decisive role in the great war. Shikhandi fought very bravely in the war till the last day. But he was killed by Ashvaththaama in the night of the eighteenth day alongwith his other brothers. His role in the epic is limited but crucial.