You could take rage mage PrC levels and able rage and cast spells same time
. Anyways yes, your legendary
monsters in planar/cosmic scale. No one else is tri-path gestalt paragon creatures (and strong monster base). So designer of cosmic planar mazes/dimensions is very possible.
However, one way or another, you all were sealed up tight by overgod because your very existence (not deeds) was too dangerous
to let be. Including benevolent monsters. Overall though story starts in that you were released from the 'seal' overgod placed you in and tells reason why he releases bunch of 'super legendary monsters' loose in cosmos once more. There are still legends of your deeds, some warped, changed, diminished or even over exaggerated ones (or some weird changes to them and most folks count it mere myth, fairy tail even).