He becomes leader in chapter 3 and 4 in The darkest hour.
Fireheart
Firepaw Fireheart or Firestar
He becomes Thunderclan leader.
Fireheart's mother is Princess, a kittypet who lived in Twolegplace. She is also the mother of Firestar's littermates, Scourge and Socks.
Firepaw/Fireheart/Firestar is the main character for a while.
Firepaw becomes fireheart in into the wild and later in the darkest hour he receives his leader name firestar (after Bluestar dies).
I don't think he kills any cat as Fireheart, but he kills Scourge, evil leader of BloodClan, as Firestar.
Oh, what a lovely question! Fireheart and Sandstorm become mates in the book "Fire and Ice," on page 317. It's a beautiful moment in their journey together, filled with warmth and love just like a happy little tree in a meadow.
He was Firepaw/Rusty the kittypet in the first book. Fire heart becomes firestar later on.
after she dies, fireheart becomes firestar, and graystripe is made deputy.
His kittypet name was Rusty, then he became Firepaw, then Fireheart, then after Bluestar died (stupid tigerstar, grrr) he became Firestar. rusty firepaw fireheart firestar[i hate tigerstar!!!] I agree I hate Tigerclaw/TigerStar :( i hate tigerstar also but he is funny,as a kit in Bluestars Prochey
After Bluestar dies, she is succeeded by Firestar (Fireheart) as leader.