In 2012, Aya's Overdive technique was used in order to travel back through time through the power of the "Overdive Device", developed by the Counter Twisted Investigation and completed in the winter of 2012.
While Aya's body is still at the CTI unconscious, Aya's consciousness is battling the Twisted in the past. Blank and Hyde Bohr can also contact Aya's consciousness in the past, letting her know about the situation and other facts and goals she needs to accomplish. The only flaw to this system is that only Aya can use the machine due to her advanced mitochondria and if she dies while Overdiving, her body will also die back at the CTI Headquarters.
Overdive is merely Aya's conscious-swapping. In the game, however, Aya's "body" is also seen swapping place with uniformed soldiers. This is only seen to the player to indicate where Aya is for gameplay purposes, thus other soldiers still see Aya as one of their own men and not as a blonde-haired woman.
Abilities of Overdive
Overdive allows Aya to jump into the bodies of various people, including SWAT, Army and even citizens.
Overdive also allows Aya to jump into the Twisted. This is known as ODK (Overdive Kill) and will either kill a Twisted or severely damage them. This is also used at the end of every boss battle as well. This is indeed a very useful ability that triggers after the target is dealt a certain amount of damage, but after ODK'ing, Aya will be vulnerable to damage for two seconds so it's best to use it while Aya will be safe from sudden damage.
Destruction of Overdive Device
On December 25th, 2013, the CTI was destroyed by Kyle Madigan and all the CTI staff were killed and Hyde Bohr went missing. In addition, the Overdive Device was destroyed so while Aya could still Overdive, she could not return to the past.
It is never really explained why Kyle destroyed the Overdive Device, making this just another plot hole in The 3rd Birthday. Maeda's first message in the mailbox says he "probably didn't like Aya diving around in the past".
Truth of Overdive
As it turns out that Aya Brea is in fact Eve Brea, it was revealed that it wasn't the Overdive machine that was allowing her to go into people's bodies but in fact Eve's own ability (with the machine only giving her the ability to Overdive to the past). Eve can dive into other peoples' bodies by altering their mitochondria to let her in.
This first happened during Aya's and Kyle's wedding after Aya was shot down protecting Eve from the "police". Eve's powers then awoke and Eve's soul automatically launched into Aya's body so that she could save her sister; unfortunately, this caused Aya's soul to shatter and for Eve to lose her memories. Hyde Bohr planned this and created the machine in order to harvest Eve's powers and to manipulate her to do his bidding.
|Aya Brea - Eve Brea - Kyle Madigan|
Hyde Bohr - Thelonious Cray - Hunter Owen - Blank - Gabrielle Monsigny - Kunihiko Maeda - Emily Jefferson - Ginger - Seamus Rose
Slacker - Wad - Stinker - Snatcher - Bean - Roller - Rover - Detector - Worm - Spitter - Mudflap - Reaper - Helix - Queen
|Babel - CTI Headquarters - Club Sacrifice - Maeda's House - North Shallows Tower - Rockefeller Center - Saint Thomas Church - Spanish Harlem|
|Cheat Codes - Feats - Outfits - Overdive - Over Energy - Soundtrack - Weapons|