Apolgies. I hate author's notes as much as the next fellow, but I felt I had to state two things up front. Well, three things. Firstly, I'm borrowing heavily from Hellsing Ultimate and the Diablo video game universe. That said, I'm not using any characters from them, just borrowing sand for my sandbox, so to speak. Secondly, if it wasn't obvious, this is a rather violent story. It couldn't be otherwise, with those two universes feeding it. Lastly, I'm still working on this, so expect errors (I am particularly bad at tenses) and welcome any useful criticism.
Footfalls thudded, echoing through the hallway as Albus Dumbledore, professor of transfiguration, sprinted towards an out of the way bathroom. Panting, he slammed into the door and fumbled it open. What he saw behind it made him pale in horror.
"Tom! What have you done?" He asked the young man in the middle of the room. Covered in blood, Tom Riddle looked up and smiled at him. "Professor! Isn't it wonderful? I found a way to make doors between places in a book. Instead of apparating or portkeys, we can just walk through a portal! I'll be famous!"
Dumbledore looked around the room. On the far wall the body of a dead girl, young Myrtle Warren if he wasn't mistaken, was suspended by spikes driven through her body at various places. Tom had apparently been using her blood to draw a pentagram and various sigils on the floor at her feet. He didn't look at those too closely, just a casual glance made his eyes ache. Never a good sign.
"Please don't interrupt Myrtle professor. She's helping me with the runes for this and if she gets one wrong we'll have to start all over again." Toms words stopped Dumbledore as he raised his wand to erase this stain on reality.
"Interrupt? Runes? Tom, have you gone mad? Miss Warren is dead! You are going to Azkaban for the rest of your misbegotten life and the best thing you can do now-" Dumbledore broke off as a newcomer arrived, panting, in the bathroom.
"Headmaster Dippett. Prompt as ever I see," Dumbledore said angrily. "You can help me clean up this mess and then call the aurors while I detain young Tom here.
The headmaster had to forcibly stop himself from vomiting as he looked around the desecrated room. "How did this happen?" He asked as in a daze.
"You, Riddle, how did you come by this foul ritual?" Riddle looked bemused at the headmaster's question. "Foul? Sir, all I've been doing is finishing some calculations I found in a restricted book about travelling. I had a note from Professor Slughorn and everything!"
Albus rounded on the headmaster as well on hearing this. "You fool! I told you to remove-"
Whatever else he was about to say was stopped by a wet ripping sound. "Oh! It seems Myrtle's finished the runes!" Tom said happily as the two elderly wizards turned towards the wall.
A low chuckle filled the room and Albus felt dread fill his whole body. "Dippett, I'll try to hold them back. You're more experienced in the actual mechanics of it than I am, you close the portal before it's too late."
With that he surprised his student by whipping out a dagger instead of a wand. Waving it in just the right pattern, he chanted a short string of words that seemed to chill the air as he said them before pointing his dagger at the pulsating body of Myrtle Warren. Headmaster Dippett, meanwhile, had begun chanting in a completely different language as he wove runes of pure light seemingly out of thin air.
With a gasp, Tom Riddle fell to the floor and started retching. "What- what happened? Myrtle? Professors?" He desperately looked around for answers to the horror that had suddenly appeared before his eyes as if by, ironically, magic.
"Eyes opened at last I see," Dumbledore said, panting, as he took a moment to catch his breath in between incantations. "You were misled by a cursed book. One that should have been removed from the library long ago." The last part was said with a scathing look at the headmaster, who ignored it and kept up his chanting.
"Cursed? Sir, what is happening?" Riddle asked, seeming genuinely scared for only the second time that Albus had ever seen. "I am trying to keep back the beast on the other side of the portal forming inside miss Warren. Headmaster Dippett is working to close it before it fully stabilises. Pray we succeed, or you will live to discover the actual meaning of the phrase 'hell on earth'."
"I don't know if I can do this, Albus," panted Dippett. "The damned thing was woven specifically to let something through. Unless we find a way of trapping the beast trying to come through, there's no way to permanently seal this hole."
Albus thought quickly. Designs and ideas flashed through his brain. A soul stone, discarded for lack of time and materials. A containment contstruct, possible but much too fragile and temporary. Only his training in the ways of the soul left a way out, but who could possibly be strong enough to contain…
"Riddle! Listen to me!" Albus shouted at the still-gibbering boy. "Fetch Hagrid. He's the only one that can help us now."
Shocked out of his near-maddened state, Riddle gaped at his professor. "Hagrid? But he's a-"
Whatever he was about to say was stopped by a horrible squelching sound. The body of Myrtle Warren burst open to reveal a swirling, reddish-black hole into nothingness. Somehow, shadowy shapes could be seen in it, darker than the black of the hole itself.
"Fucking run boy!" Dumbledore swore as he lifted both his dagger and his wand and began pouring an awe-inspiring torrent of offensive magic into the portal as Dippett sagged against the wall, exhausted.