Originally Posted by
Sojourner
Argus is already long time born and running, it is noted in 7.3 he knows almost nothing but torment.
He is talking about rebirth of the Pantheon, he was collecting remnants of souls of the Pantheon Titans across the universe and managed to get all but one (Eonar) who is key to his plan to create his Dark Pantheon.
As above, he is already long time in existence... Since the whole topic has tag SPOILER I'll just continue by saying we will use Argus's essence (as well as other Titans) to imprison Sargeras in Seat of the Pantheon. Also, he was not born fel - no titan can, most of the time Fel kills Titans; Sargeras was an exception due to how fel was embedded in him. Argus is regular titan born from world-soul, but used by Sargeras to fuel Antorus and resurrecting his demonic armies.