Well readers, if you're curious as to how strong the being is (as I said, he has ten times more power than a Mass Relay), you're about to find out.
Note that 'HIS' speech will be normal italics, and Reaper speech will be bold underline
The stasis tank exploded with glass and a sort of fluid landing all over the floor. The being hit the floor with a thud and Shepard turned his attention to the tunnel with the tsunami of Brutes, Banshees and Ravagers approaching. "Batten down the hatches guys, this is gonna get rough" he said as they took aim, however just before they could pull their triggers they were blinded by a bright blue light, the same colour blue as any biotic would be.
All the squad heard was a sinister laugh within the light and a voice, "Rough is an understatement human, you've just opened the gates of hell". With that, they heard what sounded like a sword being unsheathed and the light went blazing past them at a break-neck speed. The three figured that for the biotic to blaze past them at that speed, he had to be a Vangaurd.
Before Shepard, Garrus and Javik could register what just happened, half the base was on fire. "Joker here, what the hell is happening down there Commander. Explosions are going off like fireworks at Chinese new year." Shepard ignoring the pilots poor humour started chasing the being, following the path of utter devastation. Nothing but body parts or burned out bodies in the wake of 'him'. "Our suspicions were right Joker, that signal was alive. Whatever it is, it's PISSED and moving fast".
The squad just tried to stay focused as they pursued their target, feeling the base rock with an explosion every few seconds. However after a minute or so, the explosions stopped. This didn't phase the squad as they continued to follow the destruction.
EDI scanned the asteroid and detected the being. "Shepard, I have found him, he's outside about three kilometres from your position and moving fast. He appears to have wings. Reaper ground forces are almost completely eradicated and the Destroyer and fighters are descending on your position". Shepard and the team which were now close to the exit replied "Copy that, Cortez bring the shuttle around, we'll just have to evade the Reaper before we chase that THING".
The squad came outside and saw a level of chaos not even the Reapers could match. "Shepard I can't bring the shuttle, the Reaper has already arrived". The teams moral dropped like a rock as they knew full well that between the Reaper and fighters, the Normandy could not help them. Garrus with a great look of concern commented "Well can this get any better". What the team and the Normandy heard next was not who they were expecting to hear. "Well ain't that ironic. The one being rescued has to save the ones doing the rescuing". With a pulse of his light the team saw him on a Cliffside to their left four kilometres away.
He sees the Reaper land right next to the hellhole that has held him prisoner for so long and sees the Oculus fighters moving on his location. With one forward motion he drops off the cliff and unfolds his wings, beginning his approach on the Reaper forces. He did not need to flap his wings, instead he discharged energy out of them like a jet engine. When he saw the first six fighters move in, he made his move.
He instantly dashed to the fighters at what can only be described as the speed of light, shooting biotic energy balls from his hands at the same speed as a Revenant. The first six were disintegrated by the blasts and the other six attacked him. He barrel rolled to the side evading their attacks and replied with explosive biotic homing spikes he shot out of his wings, destroying the six with almost no effort.
With the peons killed, he turned his attention to the main course. He flew to his left so that he was directly behind the 'soon to be his little bitch' Reaper. He pulses his wings again and folds them away so that he was sent up to be level with the Reapers horns and with a gesture of his arm, summoned a 'ghost arm' that extended and pulled him toward the Reaper. Once he landed, he thought it was about time to go full power.
With blue fire and lightning surrounding him, he summoned a full body apparition of him that was ten times his size and mimicked everything he gestured. "THIS IS GONNA HURT, ALOT!" He jumps toward the Reapers beam which was charging to fire on Shepard and his team. With the motioning of his arm forward as if to grab something, the ghost mimic copied, reaching out grabbing the Reapers beam. He pulled his arm back while clenching his fist rips the Reapers beam out while crushing it. "Time to end this motherfucker" and with the newly made hole, he flew inside the Reaper disintegrating and ripping it apart from the inside-out. The last thing Shepard saw of what was left of the Living Reaper was a massive purple explosion on its back with the being flying out, leaving the Reaper to collapse.
He landed right between the squad and what was left of one of the 'monsters of the galaxy'. "Reavus", the team and the being turned to face the pile of burning metal. "Celebrate your short lived victory, you cannot stop the Reaper army". Reavus snickerd as he replied "Well you clearly weren't around ten cycles ago you noob, for it was my race and I that nearly brought you down had you not started your cycle early. Now I know that you're gonna die within the next minute, so you tell Harbinger what happened here. You tell that asshole that the Reapers worst nightmares have retuned, and you tell that festering pile of shit that one way or another I will be there in the end, ripping him LIMB FROM FUCKING LIMB."
With that the destroyer shut down and Reavus turned to Shepard and his team, powering down so he just let off a dim light and sheathing his sword which was a four foot katana back into the sheath attached to his left arm. Shepard started noticing the person's appearance now that his biotic light dimmed out. His skin was a light glowing blue colour and his body was also covered in a sort of black muscular exoskeleton armour. His face was also black and he had glowing red eyes as well as what seemed to me two metalical silver horns on his head. The last thing Shepard noticed was that his wings folded into a sort of long length coat.
"Now that's what you call an ass whupping". The three men just looked at eachother with silence and gob-smacked expressions beneath their masks as they approached Reavus. "Hmm, tough crowd. I suppose I should thank you human, 500000 years I've waited for someone like you to get me out of that tank. What's your name?". All Shepard could say was an answer and the typical disbelief questions: "My name is Commander Shepard. Who are you? What are you? What was the vision back inside?" Reavus with a 'This really isn't the place look' replied "I'll give you the brief. My name is Reavus, I come from a race know as the Necris. We are the one race the Reapers fear because we are the only race ever that can take on the Reapers head-on and trump every time. The only reason we lost is because our main military plans couldn't bare fruit before the end of our war. That was the vision I showed you, our last moments, my last moments before the Reapers captured me. I had to give you evidence that I hate the Reapers just as much as you do. Now if you don't mind, we should leave now before more Reapers show up". The shuttle landed and the four entered.
"How is it you're not indoctrinated" the prothean asked. "Because I can't. I'm an immortal energy being, the only of my kind among my kin. I can't die or be indoctrinated". With that, the shuttle left the rock and retuned to the Normandy.
R&R