Solution!

Stepping out onto the Quidditch pitch Loki, under a disguise, moved towards the betting stations.

"How can I help you today good sir?" A student asked politely as Loki moved to the front of the line.

"I'd like to place a bet supporting Hufflepuff."

"Oh? And how much would you like to bet?"

"Three Galleons under the name Gehrman Sparrow please.", Loki said with a friendly smile.

"Th-! Three galleons!?" The boy shouted losing all his composure but managed to turn it into a whisper at the last second.

"Yes, you heard that right. I'd like to bet three Galleons." Loki repeated with a smile. "What do you think? Is it possible?"

The boy stared at Loki for a few seconds with an open mouth but then frantically picked up a quill and dipped it in ink while simultaneously speaking to Loki. "Yes, please don't worry about it, you're in safe hands."

"Oh good, thank you."

Dropping the money Loki left the betting area and walked up to the stands after taking his receipt for the three galleons.

'The odds are about Six to One, meaning my three Galleons should turn into Twenty-one in the total payout.'

'Damn, no one expects Hufflepuff to win this match do they?'

'I mean I understand where they're coming from. Any match Harry has been a part of, Gryffindor has always won. Too bad they don't have a friend they can conveniently use to know the future.'

'I want to see too, how Harry loses this game.'

'Is it because of the rain? Did it obstruct his vision? But haven't they been practising all month long for this event?'

'Good thing I wore a coat with a warming charm on it to keep me out of the cold, can't imagine how numb all the players are feeling.'

The match started with both teams flying onto the pitch, doing their best to keep steady under the heavy pitter-patter of the unending rain.

Wearing goggles to keep the rain out of his eyes, Loki cast the Impervious spell on it to keep his vision free from rain.

With a clear vision of everything going on around him and his exaggerated vision that gave him a clear view of everything like he was a hawk, Loki spotted the golden snitch as it wove around the pitch.

'Should I try my hand at Quidditch?'

As Loki pondered meaninglessly on meaningless questions he found his mind drifting away from the game.

Or at least it remained adrift until the excited commentary entered his ears.

"-AND THERE GOES HARRY!! HAS HE FOUND IT!!!?? THE SNITCH!!!"

That was when Loki's eyes shifted towards Harry.

'He's flying high. Did he really spot the snit-'

Loki's eyes followed Harry and spotted the snitch about fifty feet higher than him, except that wasn't all that they spotted.

Between the clouds, Loki spotted thin dark robes fluttering as they moved in a rabid dash towards the stadium.

The clouds cleared a little as they rushed ahead allowing Loki to see something not even the teachers had seen yet.

'All of them?' Loki stood aghast.

A drop of rain slithered on his spine causing him to break out of shock.

His hand moved to his wand and he pulled it out faster than he ever had.

In the fraction of a second that it took for Loki's hand to move to his wand and pull it out of the holder, his mind came up with several combinations and permutations to figure out the best possible approach for this situation.

'I can't use the Patronus charm.'

'I can't reveal my own creation. Not that it would do much against an army.'

'I can't inform someone about it before something happens.'

'I'm stuc-'

Right then Loki remembered Hermione's wise words.

'-you just have to drag an even stronger character into the fray.'

As if a spark had ignited in his eyes, Loki's brain worked faster than it ever had to produce an entirely new spell modified from the simple sparks charm.

'All I need to do is buy time.'

'As long as I buy time, someone will be able to respond in time.'

'To buy time I don't need to defeat the Dementors but set them on a short pause.'

"VERMILLIOUS RUPTIS!!!" Loki shouted at the top of his voice while standing up.

Red sparks emerged out of Loki's wand and shot towards the sky at a speed that had to be faster than Harry's nimbus Two thousand and one since it caught up to him in no time.

The sudden action caused most students in the stadium to become shocked while the rest were confused and even angry at Loki for interfering with the game. Especially the players themselves.

Harry ducked under the spell as it wished past him and illuminated the dark clouds above.

The red light expanded like a flare and under everyone's gaze exploded into a shower of bright white light.

All the clouds that came in contact with the light exploded and vanished as if they were balloons that had been pricked by a needle.

A large circular hole became available to everyone underneath, making the rain vanish for a few seconds.

The golden sunlight that emerged through the clouds looked like a pillar that had been dropped down from the heavens.

Except along with the heavenly pillar all the teachers and the players on the field spotted the army of floating dark hooded creatures.

Not even moments later when Harry tried to brake to stop himself from flying into what appeared like a death-filled sky a burst of white light dragged everyone's attention.

Dumbledore's wand was flicked and a large bright white ethereal heavenly bird flew up from the grounds.

It moved faster than Loki's spell did and flew into the ocean of encroaching darkness without fear and under everyone's stunned gaze dispelled it all.

The dementors rushed to try and at least get Harry, but the bird created an invisible shield around him. The dementors tried for a few seconds until the ethereal bird snapped its beak and broke a dementor's arm.

The rest scattered almost immediately and rushed towards the castle.

Loki was looking at Dumbledore and his only thought was simple-'Strong.'

That wasn't only Loki's thought. Everyone in the stadium suddenly understood just how powerful Dumbledore was. 

'Impossibly strong.'

They didn't know how much stronger he was on a scale, but each one of them felt the vast chasm between him and them, especially since they could all feel the waves of happiness and positive emotions the patronus exuded all throughout the stadium.

Even as the rainfall slowly returned and started to fall onto Loki and all the other students, the patronus radiated a sense of warmth and comfort.

It did all of that while flying nearly a hundred feet high in the sky.

Loki was shocked, yes. But along with the shock he'd also immediately grasped a key to solving one of his problems.

The fog in his mind that Hermione had cleared a little became more transparent as a small but bright light emerged in it.

'This…I can use this…'

'The key was surprisingly simple…'

'How did I never think of this?'

'I just need to involve Harry Potter in my plans somehow.'

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