Here is how Apocalypse is alive goes in Ryan F-Freeman's Adventures of Transformers: Prime.
[the episode kicks off with the place where En Sabah Nur was destroyed in 1983]
(suddenly, the wind repairs the destroyed Armour)
(the dust then reforms into a skeleton)
(then lightning strikes and flesh returns)
(he looks around and sees no one around)
(he then senses something)
Apocalypse: Sirens.(he gets up and knowing that he can't fight their allies alone, he heads to the Fire Nation Capital prison, and puts on a cloak to hide his face)
Apocalypse: They will not stand in my way this time. Their time is running out.
(the theme plays)
(The theme ends)