Karna looked at his guild members running towards the island from a ship which will return home after every wizard taking the tests exits it. He counted the number of people who will be left trapped in the island for the next seven years.
A total of eighteen including himself. But he also knew the fact that it was necessary. Hades will come to Zeref with his keys and realising the horrifying realisation, Zeref will kill Hades. Zeref was a wizard who managed to siphon the curse energy. He created it by channelling the centuries worth of despair he felt while his curse took the life of everyone around him.
Just sensing the keys containing the despair of thousands will sentence Hades to his death by Zeref's hands. But at the same time's Zeref's attack magic will bring forth Acnalogia's attention. Plus, the cluster of curse energy will not help the matter at all. All that despair will make Acnalogia act until he finds a target to fight that lasts more than a single attack from him. The Tenrou Island fight was satisfying for Acnalogia even though it did not make him use his full power.
Plus, the fairy tail members used Fairy Sphere and disappeared right at the moment Acnalogia's attack landed, making the dragon believe that he had taken down his enemies and was satisfied enough to go back without creating any more problems.
Now imagine a scenario where the fight did not happen. Hades still comes to Tenrou island to find Zeref, Zeref's magic along with the presence of the curse keys will bring forth the attention of Acnalogia, but instead of facing a wide group of wizards and dragonslayers, Acnalogia will face no one as Karna was sure that Zeref has a way to hide himself from Acnalogia.
Seeing that his prey had escaped, Acnalogia will get angry and will attack the closest human settlement, the Harjeon port. This subsequently will start a war that will wipe out at least a quarter of the population of Ishgar until Acnalogia is satisfied. And these statistics are the best possible situation according to Karna's calculation.
So, he has no choice but to make sure the timeline happens in the way it di last time.
"Don't worry so much kid, whatever you are planning to do. You have our full support" a sudden voice came from behind startling Karna as he had not felt anyone's presence behind him.
Makarov came up and sat next to him while watching Fairy Tail members trying their best to survive all the specific traps Karna had made for them.
"What do you mean old man, the traps I made does not even reach the quarter of the intensity of the traps I made for Laxus all those years ago" Karna said while trying to shift the subject.
"You really have a bad poker face kid, every other children who was with you for the last few days knows about it as well, so tell me kid. How bad is the trouble we are going to face" Makarov asked with a serious expression this time.
"We can die, gramps. If the plans I made does not go well" Karna finally admitted as he also felt Mavis's presence nearby.
Makarov took a deep breath.
"Could it have been avoided?" He asked.
"No. either this plan or the destruction of the entire Ishgar."
"Hmm, do your best. I know you will save us all" Makarov said calmly as he looked at the horizon.
He did not ask what the trouble was, he did not ask what the plans made were. The only thing he was sure of was that his child loved every single person within the guild. And Makarov knew that Karna would die before he lets anything happen to them.
At a small distance from where Makarov and Karna was talking, the other S class wizards where hiding while making sure to reduce their presence to their absolute limit possible so as to not be sensed by Karna.
Erza clenched her fist in anger. She was not angry at the fact that Karna had brought them here while having knowledge of a danger that might kill them. She was angrier at the fact that Karna did not feel like they were strong enough to know the truth.
'It's the same. Just like when Rob died, I'm still too weak' Erza bit her lip in anger at the thought. Then she felt the presence of Juvia and Lisanna who were approaching the battle ground.
The others S class wizards detected the other members approaching as well. So, they too went on their way to test them. Even though they did not show any outward actions, they too were frustrated at the fact that Karna considered them weak.
While this was going on, the other challengers were cursing the S class wizards for the challenges they had to face in tunnels they chose. But after some time, they began to have doubts whether the selection of tunnels were random. Even though they were unable to find out what happened to the other contestants, their instincts were telling them that their senior prankster had a hand behind everything that was happening to them.
Natsu and happy had to move through a corridor that had moving floors. But when Happy tried to fly, he was pelted by a fish which turned out to be stone when Happy tried to bite it. The rock fishes were falling again and again while a sign came up saying that one of the fish was real and seeing that all of them are indistinguishable, Happy was biting each and every one of them, hurting his teeth while Natsu was suffering the motion sickness.
Lucy and Meredy was having a harder time than usual. Because of the breathing technique and advice given by Karna, Lucy had grown to be quite a formidable force. So, Meredy had chosen Lucy as her partner for the S class trial.
Right now, they were going through a muddy river filled with worm like beings that were biting them again and again. When Lucy tried to use her keys, it was suddenly snatched away by the worm who put it on the other side of the bank, her whips also had the same fate. Meredy had thought about using her empathy magic to control the worms, but some kind of instinct told her that the trap was prepared for them as the worm had attacked both Lucy's whip and her keys without any hesitation.
The reduced anger she had towards Karna began to rise up once more as she moved through the muddy swamp while enduring the worm bites.
A/N- hope you like it.