****Nurmengard, 31 November 1981, the topmost prison cell********
The fools, they thought he was kept safely in his own fortress! They might control the great magic that was involved in the creation of the fortress but it was he who controlled the back doors.
And today they would pay for their foolishness, he had been content to wait out his days, after all he was beaten, his power was broken, but this night on all hallows eve the dark magic in the air was wild, indeed it was like a storm had broken loose in the winds of magic.
The storm revitalized him; he felt decades younger, he felt his magic again after not having it used for so long it felt like spring had come after a extremely cold winter.
He would use this to take his revenge, He might not live to see it but he didn't mind, his live was spend already, he would never get out this much he knew but he legacy might live on.
With a wave of his hand the prison bars parted before him allowing him to exit his cell. He moved down the stairs step by step struggling to move his bony legs. As he moved down he heard them, the guards.
He saw them sitting in the guard room enjoying a Halloween meal without a care in the world, after all they thought ''What have we got to worry about? Crazy old Grindelwald up in the tower? He hasn't got any power left.'' But they are wrong! Even without the Elder wand I still poses more arcane knowledge than any other human in existence.
HE fell on them like the ice cold northern wind; the first guard got a nice and simple cutting curse to the head, decapitating him like the French used to do to royalty.
The second got a blood boiling curse right between the legs making him scream in pain and left him unable to cast anything while he was slowly being cooked from inside out.
The third and final guard just got a stunner to his head for he would the former dark lord his goal quite nicely.
As he moved down to the secret dungeon which nobody had ever found ever since his fortress had been conquered the body of the stunned guard floated after him like a feather caught in the wind.
There he found his summoning circle which he had always had used to communicate with daemons for knowledge and power, engraved into the stone with the bones of a Demontor. In the middle of the circle the unconscious guard was put to rest while the old dark sorcerer stepped just outside of it.
The old man started chanting with wicked intent:
Veni adme,
Demonexmundoest
Carnemmeam,respondeproindignis
Demon(Deus) qui responditnominiangramainyu
The circle began to emit a crimson light casting the room in a ominous light.
Radix enim omnium malorum, responde mihi,
tenetnoctisinvocaverunttein
Omne quod estin mundo,etesse
The wind was picking up in a room without wind.
Shut(impleo). Shut(impleo). Shut(impleo). Shut(impleo). Shut(impleo).
Repeteresingulosquinque.
Simplex,quondamfrangat.
A crimson vortex formed over the circle, covering it completely in that dark red wind.
Nuncin concilioadosencraveddæmoniumsuis.
Daemoniumet evocantfero(Dei)ANGRA MAINYU!
And as strangely as it came to be the vortex left leaving only the previously unconscious man standing in the circle.
''GrINDeLwaLD, wE dID not think yOu woUlD call Up Us AgAIn.''
Spoke the being which wore the shell of the prison guard in a twisted voice which sounded like two people were speaking at the same time.
''With the regaining of my power for this single night I have decided to make them pay, make them pay for my defeat, make them pay for my imprisonment and most of all make them pay for the stealing of my power!''
''WhAt dO YoU oFFer in ReTurn?''
''You will be remade, your soul will shall be given human form to do whatever you like, my offer is an offer of freedom'' the old man spoke with a sinister grin.
''ThEn We hAvE a AgrEeMenT'' the being spoke with a unnaturally large smileon the possessed guard his face.
Suddenly the vortex came back more intense then it was before. Outside the great fortress of Nurmengard a true storm had broken loose, stinking at the fortress, again, again, again and again, again, again and with a final mighty stike of lightning the wall of the fortress fell, like it had been hit by Thor's hammer.
Grindelwald with a big grin on his face stepped right into the vortex of crimson energy and was torn apart within a second.
It the exact second that one Harry Potter was hit with the killing curse in Great Britain, a wave of dark energy was send all across the world alerting every Witch or Wizard to the emergence of a new evil of the likes never been seen before.
From the circle stepped a man, he was about 1.85m and wore Black robes and a crimson cape with a hood from which two ominous yellow eyes shone.
As the Man walked away to explore the modern world he left only an empty fortress behind.
*******13 Years later******
*******Hogwarts, 1994, the field infront of the black lake**********
As the Hogwarts students looked around in search of the Durmstrang envoys for the Tri-wizard tournament, one Colin Creevy spotted them.
''THERE IN THE SKY!'' The boy exclaimed. And indeed far away in the sky was a tower, a tower build on a small island was gently floating towards Hogwarts.
After what seemed like a eternity the Tower finally came to a halt just above the crowd and from the bottom of the floating island a staircase spiraled down from the opening in the island.
As soon as the staircase hit the ground a line of people came walking down, the first one to reach the bottom was a stern old man, dressed in white and blue clothes with a goatee.
After that came Krum the famous Bulgarian Quidditch player, followed by the rest of the students. With a smile Dumbledore walked up to the stern looking man and held out his hand ''Rohen, what pleasure to see you'' he said, the so named Rohen smiled and shook the hand '' Indeed Dumbledore it has been some time'' The disguised man said.AN) This was just something I felt like writing if somebody wants to pick it up feel free to but be sure to send me a PM about it. The Demon/Rohen looks like the Young Rohen from Spellforce: the order of dawn and when he is disguised as the old one. What he did in the 13 year timeskip is really up to your imagination, it is probably something along the lines of gathering influence, reputation and just exploring the modern world.