Tallstar is a skinny black-and-white tom who is only called that because the name Longtail was already taken.
Tails are measured in length, not height.
In The Prophecies Begin Edit
He does a bunch of stuff. Dies in...Sunset?
In Tallstar's Revenge Edit
Tallkit was the wimpiest kit in the WindClan nursery, constantly bullied by Shrewkit. Shrewkit's brother Barkkit was less of an asshole.
Tallkit's mother Palebird was constantly depressed because Tallkit's littermate, Finchkit, died at birth. However his father Sandgorse seems bizarrely unaffected by this, and is obsessed with his son becoming a tunneler even though Tallkit wants to be a moor runner. Wait, wtf are tunnelers and moor runners? I know right. Just google it.
Tallkit is dreading becoming a tunneler like his dad, and is surprised when Heatherstar the pink cat makes him a moor runner apprentice instead. This is the first sign that tunneler importance in the Clan is fading, because there are way more moor runners (normal warriors) than tunnelers. Sandgorse is outraged.
Even though Tallpaw is training to be a moor runner his father makes him go down the gorge tunnel. It floods, nearly killing them, and makes Tallpaw even more terrified of the tunnels but Sandgorse is pretty chill about it.
At some point a bunch of rogues visit WindClan, as they apparently do every year (this Clan is apparently chock fulla secrets). One of them called Reena is v cute and interested in Tallpaw. Reena's rogue friend Sparrow gets caught in a collapsing tunnel with Sandgorse, and Talltail is fucking furious. (Is Talltail a warrior by now? Was he one when the rogues arrived? Eh, who cares).
After the rogues leave, Talltail leaves the Clan to go after them and exact his revenge on Sparrow who he thinks basically killed his father. Along the way, in a Twolegplace, he meets a kittypet called Jake who seems like a bumbling idiot at first but is actually a very cool and brave (if a bit simple-minded) cat. Also yeah that's Rusty's dad. Ever wonder why Tallstar supported Firestar so much?
Jake comes with Talltail on his revenge quest, and when they eventually find the rogues Talltail spends like a day planning Sparrow's death but then forgives him in the end, realizing how fucking crazy he's acting. Talltail and Jake leave, and Talltail's crush stays in Twolegplace (I'm not kidding, it's been revealed by the Erins that Tallstar kind of fell in gay love with Jake and that's why he never took a mate). Talltail returns to WindClan, which he said he'd never do, and gets Deadfoot as an apprentice and stuff. Did you know he was called Hopkit originally? How cruel is that?