Who becomes leader when firestar dies?

It is likely that Brambleclaw will become leader after Firestar since Brambleclaw is currently the deputy. However, anything is possible.

Some possibilities for the new leader include:

1. Brambleclaw
2. Cinderheart
3. Lionblaze
4. Dovepaw
5. Graystripe
6. Cloudtail

There are many other possibilities as well.

Answer to above answer:

It has already been confirmed that Brambleclaw nor Greystripe will become leader after Firestar.

Another thing that I have noticed is that Erin Hunter never uses the same leader name twice. Example: The leader of Skyclan when they were forced to leave the forest was named Cloudstar, so Cloudtail well not become leader after firestar dies.

Lionblaze becoming clan leader is a posibility, and so is Cinderheart.

Also I know people keep asking is 'how many lives does firestar have left?'

He has 2 lives left at the end of fading echos, the second book of omen of the stars.

It has also been confirmed that Firestar is going to die at the end of the fourth series.