I want to murder all humans [closed]

Extermination might help in your, er, endeavour.

Extermination:

to get rid of completely usually by killing off

In Science Fiction contexts, Genocide has been used to refer to eliminating an entire species. An example of this is in the Star Trek episode I Borg, many object to commiting genocide against the Borg.

I think your dodo example is revealing - seems like extinction should do fine. If you want to kill all humans, then you want to cause human extinction, or make humans extinct.. And you could insert any other species in that template.

@LarsTech's answer is good. Another good word is extirpation. This word, which literally means rooting out, is the usual translation for the word Hitler used (ausrotten, to root out).