He was Firepaw/Rusty the kittypet in the first book. Fire heart becomes firestar later on.
Fireheart's apprentices were Cinderpelt, Cloudtail, and Brambleclaw.
Firepaw becomes fireheart in into the wild and later in the darkest hour he receives his leader name firestar (after Bluestar dies).
Fireheart is a loyal, trustworthy cat. He is also brave and very protective.
The cat on the cover of "Rising Storm" by Erin Hunter is Fireheart, the main character of the Warriors series. He is depicted standing on a ledge, looking out over the ThunderClan territory.
For your screenname, just type in fireheart. If you can't get it, that means someone else already has it.
Fireheart's sister Princess, offered one of her kits to him so that it could train to become a warrior. Fireheart ended up bringing Cloudkit (Later Cloudtail) into the clan :)
Fireheart
Fireheart's mother is Princess, a kittypet who lived in Twolegplace. She is also the mother of Firestar's littermates, Scourge and Socks.
The first series is from Fireheart's point of view, but the second, third, and fourth series are from younger cats' point of view (though we still do see Fireheart since he's still a ThunderClan cat).
Some say Brackenpaw and Cinderpaw. Others, Fireheart and Graystripe. I know for a fact that it is Fireheart (later Firestar) and Graystripe it could be fireheart and cinderpaw
Fireheart becomes deputy of ThunderClan when the former deputy, Redtail, is killed in battle. Bluestar appoints Fireheart as the new deputy due to his loyalty, courage, and strong leadership skills, despite some initial reservations about his past as a kittypet.
I don't think he kills any cat as Fireheart, but he kills Scourge, evil leader of BloodClan, as Firestar.