A guy at the Japan Fanfest tested the WAR's Mythic G.axe.
He reported:
-Aftermath gave +50 attack
-Aftermath lasts 30-60 sec depending on TP
-Normal crits do ~200 but crits during Aftermath do 900-1000
-Triple Attack that seemed to proc the same amount as sea weapons (he isn't sure if the Triple Attack was from Aftermath or from Berserk)
@Junyi:
I read that too but I believe the 900-1000 spikes he was getting were do to a hidden effect similar to the 2.5x - 3x zilart relic hidden multi-damage procs.
As for the triple attack I think what people are saying is not that it grants triple attack, because sea weapons only grant double, but sea weapons are (were) the only current form of "occasionally attacks: x" which allow another multi proc trait to proc at the same time.