Harry had just jumped into the water and immediately cast the bubble head charm and the point me charm similarly to the others who had trained under Reima. He remembers Moody telling him about a specific route that'd be easiest to travel and dips low against the lake bed to follow it.
The route itself isn't anything but a long ridge that digs a trail for what seem like miles. Harry swiftly follows it and isn't bothered by any sea creatures, he can see a few but they don't dare go near him... Or is it the trench? Either way he wasn't going to look a gift shark in the mouth and continued on under he eventually found the Merman village.
It looked like a ruins that'd fallen into the lake from the land, however it seems as if these creatures didn't mind it and made it their home regardless. A few minutes of swimming reveals four large stone pillars with chains connecting them to figures who're floating in the water. Hermione, Cho, Fleurs sister and... Reima? The person of his focus didn't seem as pale and lifeless as the others as Harry thinks he can see him floating there with crossed and and tapping his foot as if impatiently waiting at a line...
Harry swim up to him and almost chokes when he sees Reima's cat-like eyes stare back at him, he smirks and points at Hermione with his thumb.
Harry "Why-How are you still awake?" he asks loudly, his question barely understandable due to the water mangling it in transit.
Reima hears it regardless and shrugs, not opening his mouth to answer, partly because he can't speak underwater.
The two speak with their eyes for a few more moments before Harry goes over with the intent to free Hermione and bring her back. He's also occasionally eyeing Gabrielle but Reima signals that he's got it handled. Trusting in his words Harry nods, shoots the chain with a reducto and begins to leave with his hostage, only to almost be knocked over by a speeding blue shape with many teeth.
Krum had transfigured himself into some sort of shark-human hybrid and viciously bites at the chain holding Cho but finds his teeth are unable to pierce the metal. He growls audibly through the water and retrieves his wand from the inside of his pants and blows the chain to smithereens, causing fragments of it to hurtle through the water at the others.
Reima frowns and uses his telekinesis to change their paths so as to avoid injuring Hermione or Gabrielle. He then glares at Krum who shivers momentarily before turning his glassy fish eyes towards Reima. He sees his rival simply floating there, vulnerable, weak...
Krum immediately gets a couple ideas on how to get revenge on this person who had caused him so much trouble. His Headmaster had even encouraged these thoughts which made them all the more easy to fantasise about. His rows of serrated teeth open and clench in anticipation as he slowly swims towards Reima, not expecting him to be able to do anything except float there.
Reima cannot help the smirk that finds it's way onto his face as Krum approaches him, maybe he'll change him mind at the last second but he doubts it. Krum swims around him as if trying to provoke a response before going up to Reima's right hand and attempting to bite down on it. Only to be blown away by a spell from Harry who's looking at him furiously.
Harry hadn't expected another champion to attempt an attack on a hostage but he probably should have given Reima and Krum's history together. The surrounding Merman quickly retreat as they recognise a fight is about to start, they do not wish to be caught in the cross fire as a few had already been injured by the metal shrapnal by Krum earlier.
Krum quickly spins and recovers from the spell he'd been hit with look at Harry who's still got one hand on Hermione to get her in the water. The shark-man gives Reima another glance before swimming quickly to Harry, not realising that going past Reima was a bad idea.
*HRRK* A weird sound echoes in the water as Krum bends over as if he'd just been punched... Well, Reima had just punched him so it was the correct reaction, he hadn't used much force in it and the water resistance prevented the subsequent punch from knocking Krum out completely but Reima felt that he broke a few of the Bulgarians ribs.
While Krum in bent over and trying to catch his breath Reima throws him away from where Harry and Hermione are, once done he looks at Harry and points towards the surface.
Harry shakes his head, Reima didn't have a wand and was underwater against a transfigured Krum. He'd be torn apart if he didn't do something.
He casts a couple stunners at Krum, hoping he was bespelled or something similar to attack them, Krum easily dodges the slow moving red projectiles and tries to swim at him, this time giving Reima a wide berth
However Reima isn't about to let Harry take all the fun, he heats the chains up around his legs until they become a molten mess and quickly start leaking towards the bed of the lake. Once done he kicks the water and propels himself towards Krum while utilising his telekinesis to get the small edge he needs to catch him.
Krum is shocked to find Reima appearing before him but is even more confused when Reima's arm bursts through his torso where his heart used to be...