The 12th Doctor is the 12th incarnation of the protagonist of the Lego Doctor Who universe. He met his end after attempting to escape the Daleks on the recently brought back dalek cruicible.
After his 11th incarnation finally met his twelth hour he regenerated into a calmer and more human figure. He had his first adventure when he went back in time to Christmas 2009 and landed only a few feet away from a hospital then fell to the ground after saying "Hello, I'm the Doctor!".
But before he could actually fight to save the planet from the terrible alien menace he went into the TARDIS to get some new clothes because his old ones were taken from him and he did`nt want to save earth wearing a hospital gown and pyjamas that didn't even fit him.
After 3 hours of fighting the alien from the other side of the galexy he said goodbye to a soldier he met during the amazing adventure so the Doctor went on other adventures around time and space like: fighting what was left of the Daleks, defending earth from cybermen, meeting his old incarnations including the parallel version of his tenth incarnation while fighting the deadly entity known as the Nameless One, who managed to take control of his body as well having his memories and the ability to get into the TARDIS but with the alternate tens help.
While he was freed from the Nameless One's control the Doctor thought of a way to defeat him by throwing him into the rip he was stranded in for millions of years and sacrificing himself to save the world by using himself as a sheild so the energy of the planet earth that powered everything went into him but at a cost. Him regenerating for the 12th time. Luckily he poured it all back into the the power station and live to see another but then he fell of the edge of the scaffholding and grabbed hold of a cable and started to worry again about regenerating but as fate would have it the alternate ten was there to save him.
Both Doctors got into the TARDISes and said their goodbyes sending the alternate ten back to the parallel world to live his last few days until he faces a man and a sun.
Two weeks later the doctor made a redesigned TARDIS and was nearing the end of his 12th life. Then suddenly he got a strange visitor who told the doctor not to go the planet he was told to go to.While the doctor was gonna trycut him off the signal but he somehow teleported away before he could switch him off the signal while in mid flight.
While on the planet he encounted both incarnations of the Master which he defeated in the end but was captured by the Daleks and sent to the new Dalek Crucible which was built after another Dalek (though not dalek caan) brought the rest of its species back from the Time Lock sealing the Last Great Time War. The Doctor confronted Davros, and blinded him for a second in order to make his escape, but he had to find a way across a pit of energy which he did attempt to do but fell in to the pit of zed-neutrino energy that damaged his cells and caused him to regenerate for the 12th time, making him immune to radiation poisoning because he was regenerating in it.