Suddenly, Naoki Kashima's hologram appeared on one of the projectors, his face stern.

"Osamu," there was no honorific, "I have a job for you, Takeru, Hikari, Mewtwo, and Xerneas. And by you, I mean that you will have to personally get out in the field." That last part caused Osamu's face to blanch.

"But, Boss Naoki -" the 18-year old said.

"No buts; your scientific and magical expertise is needed. Besides, you'll like this job. Do you know of one Minato Arisato?"

"Vaguely," Osamu Akiyama spoke, "a valiant hero, sacrificed himself to defeat [i]our[/i] Nyx, in a way that erased all evidence of his existence on his Earth, including his friends' memories of him. Are you saying it's finally time to rescue him?" The wheels began turning in Osamu's head; Takeru's Crest of Hope was the perfect counter against Persona!Nyx's enabler, Erebus, aka the human collective wish to die. 

It just had to be amplified...

"Aye, aye, sir!" shouted the boy, "I'll get right on it!"

[b][i]Flash Forward[/i][/b] 

Osamu Akiyama walked beside Takeru and Hikari Takaishi (now in their late 20s and married), to Tokyo Tower; Mewtwo was also disguised as a human, while Xerneas was in a Poke Ball. Their plan, or rather, Osamu's plan? Modify Tokyo Tower to amplify the power of the Crest of Hope, and, just in case, the Crest of Light, in order to drive back Erebus and keep him away for what Osamu hoped was millenia; enough time for Minato Arisato to live a full life.

Once they got there, Osamu spoke:

"Duo," Mewtwo's fake name, "time stop."

And time stopped, allowing Osamu to take out his Hypercube, aka a box that contained a dimensional pocket, which in turn contained objects larger than the box itself. Basically, a sister technology to Poke Balls, only meant to contain nonliving objects.

From the Hypercube came out what seemed to be a mix of an antenna and a Tesla Coil, a tall, four-meter high monstrosity with a circular knob at the top, and spiky extensions jutting out from the shaft.

"The Hope Amplifier," Osamu said, "Takeru, you and Hikari activate the power of the Crests within your hearts, and focus it on the Antenna. Said Antenna would then extend its signal all over the world. I, Mewtwo, and Xerneas will guard you against Erebus, should he manifest."