WHO KILLED TALLSTAR??

Tallstar died of age, hunger, and maybe a bit of sickness from a rabbit poisoned by twolegs.

It's this stupid character called Agedeath. UGH, they are SOOO ANNOYING! They keep causing cats to grow old and die. I mean, heck, they killed Tallstar! TALLSTAR! What did he do to them to kill him? NOTHING.

...Oh, and this is a spoiler, as if you couldn't tell already.....

Somecat probably took away one of his lives but his last one was tooken by old age