Season 3 of AMC's show title Breaking Bad. By the series finale, he's a starkly different character than the one that audiences were initially introduced to.
In season 3, the show brings in Gale Boetticher (David Costabile), a surprisingly good-natured, highly intellectual chemist. He works as a cook for kingpin Gus Fring, and his praise of the purity of Walt's meth leads to the main character being brought on as a member of Gus' team. Unfortunately for Gale, different twists and turns cause season 3 to end with Jesse gunning him down in his apartment. And once Walt's brother-in-law, Hank (who's also a DEA agent), is investigating Gale's murder in Breaking Bad's season 4, he gathers clues that point him toward the deceased chemist having been the Heisenberg that he and his colleagues have been chasing.
But although pinning his deeds on Gale could be a perfect way to keep dodging law enforcement, Walt doesn't let him take the fall because of his extraordinary ego. He's an extremely intelligent man, and he knows it - beyond a level of mere healthy confidence. Judging by some of the drug operation's notes that have been intercepted, even Hank, who holds criminals in such low regard, calls Heisenberg a "genius." And the idea of not getting the credit for that so-called genius, of someone Walt thinks isn't on his level receiving the legacy for it appears to be something that Walt cannot take. Despite being able to stay off Hank and the DEA's radar for highly illegal actions, Walt can't accept someone else going down as Heisenberg. As self-sabotaging as it is, he inspires his brother-in-law to keep digging for the real mastermind.
His inability to let his dark legacy be attributed to Gale speaks to Godfather series. A man takes up a crooked life in order to benefit his family, but, along the way, he discovers and embraces the darkness within that he never previously knew was there. And not only that, but he has an undeniable knack for using it. And, for Walt, that talent and subsequent power become things he implicitly values and has a twisted sort of pride in.
This is overtly conveyed via the famous "I am the one who knocks" scene and when Walt its to Skyler that he immersed himself in a life of crime because he "liked it" and "was good at it" toward the series' conclusion. He has pride in his abilities and his work as Heisenberg. Throughout Breaking Bad, Walt's ego wreaks havoc on his life, the lives of his family, and plenty of others. And even when Gale can posthumously help ensure a certain level of safety, Walt's need for validation of his own self-perception simply can't allow it.