Bruce Timm’s contribution to DC’s Animated Universe has been significant, to say the least. His genius helped create some of the most iconic works in animation, understanding the characters in a way very few at the time were able to. The one series that perfectly encompasses the effect he has on projects is Batman: The Animated Series.
Batman: The Animated Series

Batman: The Animated Series
Being known as one of the best versions of Batman, the series was perfect in every way possible. From the voice acting, to the animation, and even the storytelling; it was ahead of its time that even now, shows find it difficult to meet the standard it set. The biggest reason for such success is because the studio, Fox, trusted that the creators knew what they were doing with the character.

“They would have to offer it to me”: DCAU Legend Bruce Timm on Working on a Live Action DC Movie

Despite this, it would seem that even they had some lines they were unwilling to cross. Timm revealed that when he was working on the series, he had an idea he desperately wanted to put into the story. Although Fox completely rejected it, he got his wish 20 years later.

Bruce Timm’s Bloody Wish

Although Batman: The Animated Series found a huge young-adult and adult audience, the series was directed at a younger audience, having an age rating of TV-PG. Such a rating meant that Fox was very careful about what they allowed to be shown in the series, trying to avoid angry parents. During an interview with ScienceFiction.com, Bruce Timm revealed that such a limitation made it difficult for him to get one idea approved.
Bruce Timm's Batman: The Animated SeriesBruce Timm’s Batman: The Animated Series
The animator revealed that when he was creating the series, there was a part where he wanted the Caped Crusader to turn into a vampire. He was inspired by the character of Nocturna, who is famous for being sensitive to light and having pale skin. Wanting to make her a vampire, he wanted her to transform Bruce Wayne into one as well.

“There’s a character in the comics called Nocturna! And it didn’t get much past the idea phase, we floated it past Fox Kids and they said ‘Nope! No Vampires!’ and I said, ‘Well what if he wasn’t really a Vampire?’ And they said, ‘No Vampires!’” said Timm.

Batman: The Animated SeriesBatman: The Animated Series
When Timm was running the idea past Fox, it was immediately shut down. On top of not approving Batman becoming a vampire, they also turned down the change in Nocturna’s character. They seemed to completely oppose the idea of having vampires in a children’s television show.

Bruce Timm’s Idea Got Its Moment In The Sun

Although Bruce Timm tried multiple times to change the studio’s mind about Batman turning into a vampire, he was unable to, and Batman: The Animated Series ended with the Dark Knight having never tasted blood. However, this is not to say that the animator was never able to execute his wish. The 2015 film, Justice League: Gods and Monsters, was co-written and co-produced by the animator, which gave him quite a lot of control over the direction of the story.
Kirk Langstrom in Justice League: Gods and MonstersKirk Langstrom in Justice League: Gods and Monsters
Timm decided to use this power in the right way and finally executed his wish. In the movie, Kirk Langstrom is a vampire Batman, who patrols the night and protects Gotham City in the absence of the Sun. Although the character usually assumes the identity of Man-Bat, such a change was more than welcome by fans and Timm got to do what he had been wanting to do for 20 years.