It would take an idiot to not realize that this dragon was leeching off the mana that radiated from the crystal and saturated the molten metal of the lake. Nick was no idiot and could easily recognize this fact and sigh as he shot around the huge caverns airspace to avoid the dragons attacks. To make matters worse Nicks senses told him a fact about the dragon that had him conflicted about killing the beast as well , it was tier five. Not the weak sort of tier five either like Slytherin who hadn't gone beyond the entry point of that tier but full on solidly within the tier.-
Nick was conflicted about killing the creature because he was well aware that this could very well be the only tier five dragon on the entire planet and was an entirely unknown species to boot. Simply killing such a thing for his own convenience when it wasn't strictly necessary just didn't sit right with him. "BOOM!" a blast of flame on a nearby wall said that the dragon itself had no such issues about killing him however as it wildly attacked after the blinding spell took hold.-
One might be wondering how Nick wasn't already dead against the dragon if it was two whole tiers above him and this would be a good question if it was a wizard. Magical beasts however functioned differently than wizards and other intelligent species such as goblin when it came to tiers of power. A normal dragon was actually tier four on average which means they should be as strong as Dumbledore and yet they could be restrained by even tier two wizards with the right strategy. The reason for this was because while their power and mana levels were well into tier four they were basically just great big brutes that lacked the versatility and minds required to fully utilize this power like wizards do.-
To put it bluntly this dragon while powerful was just flinging around it's power without and direction or restraint at all which was of course dangerous but only if Nick was an idiot and let it hit him. Despite their lack of intelligence dragons weren't stupid beasts by any means so it didn't take long for this one to realize that Nick couldn't be gotten in this way and switch up tactics.-
To be specific Nick watched it dive back under the molten metal of the lake and vanish from his magical senses. It couldn't be helped as the molten metal was constantly radiating mana from the crystal that cut off his perception at the surface of the lake. This made Nick vigilant as he knew that this meant that the beast could try and ambush him from beneath the metal. To prevent any accidents he flew to the top of the cavern and summoned a double layered shield charm as he watched the molten metal for any signs of movement.-
It was hard to tell what was movement from the dragon and what was the natural flow of the molten metal until the spot right below him sink downwards noticeably and he shot to the side just in time to avoid a blast of flame directed at his previous position. He didn't escape entirely unharmed however as his left foot got hit by the edge of the attack and was horribly scorched as a result. "TSSSS!" He hissed in pain and grit his teeth to stop himself from screaming and tried to maintain his focus on surviving and defeating this dragon.-
'I can heal the damage later if I survive that long.' He thought seriously as he never stopped moving to prevent another attack like that. This clearly got the dragon impatient as it began to visibly chase him from beneath the metal causing large amounts of disturbances on the surface as it did so. "Glacius!" Nick said loudly and a dense amount of icy air shot out of his wand towards the molten lake below and struck it in a wide area "RAAAAAAAA!" the dragon screamed in anger and pain as the hyper cold air clashed with the hyper hot metal and more importantly dragon beneath it.-
What happens when a super hot material is rapidly cooled? If you thought it becomes brittle and rigid then you are correct and this sudden chemistry lesson was learned by the dragon as well. The frigid magics struck it's scorching hide and caused it to crack and peel apart as it was moving a lot and thus created a nasty looking wound on it's back. Nicks attack did as intended however and forced the beast to the surface to keep the molten metal from damaging it's exposed flesh. While the dragon was clearly adapted to living in the molten lake that only really applied if it's hide was fully intact which thanks to Nick was no longer the case.