Kai used the tree branch and stabbed it into one of the tiger-like figure's head then kicked its body while simultaneously using it as a leaping foothold and headed straight for another tiger-like figure. 

"[Compressed Water Blade]."

Kai hit his fist into his open palm and the fist was suddenly covered in water which he pulled like a sword being pulled out of a sheath. The water took the shape of a sword and looked as if it was crystallized but in reality, it was the water being compressed so that it wouldn't burst apart.

If you pour water from a bucket aimed at a stone pillar, the pillar would simply get wet. Water by itself is almost harmless but when affected by other variables, let's say that instead of normal water, it was compressed water, enough to have pressure of a thousand feet below sea level, it would chip away at the weak parts of the pillar. But what if it was pressure from the bottom of the ocean? The pillar would be sliced apart as if it was made of cheese.

With magic, Kai now had an unstoppable blade in his hands. Normally, it's impossible for pressure from the bottom of the ocean to get to the surface, that's why the amount of mana consumption it takes to use this blade was immense. Unlike ice blades and others of the same series which only required a small amount of mana at the start and mana for repairs, water blades take over a hundred times more mana in a battle.

Kai created a small dagger of ice and stabbed it into the floor which allowed him to stop. He took a piece of rock from the floor and flicked it towards the tiger which forced it to raise its head. In that instant, Kai vanished from his spot and appeared below the tiger. He then sliced upwards with his compressed water blade and with little to no resistance at all, the tiger-like figure's head was separated from its body.

At that moment, the tigers roared and began to burn. Their auras soared and their entire bodies were covered in flames. Kai had no qualms and simply charged forward. Water puts out fire, now that he was sure they used fire, what would he need to be wary of?

"[Wetsuit]."

Kai's body was suddenly covered in a thin layer of water which flowed around his body. The embers and area attacks of the tiger's flames were put out in an instant. One of the tigers near Kai was angered and swiped its paw at Kai but with calm movements, Kai sliced the paw clean from where it was attached to and kicked the tiger's body. Not a single burn was on his body because of the suit made of water.

This wasn't a battle, it was a slaughter. The tigers couldn't even hold against a single attack nor could they land a blow. New figures began appearing, lions, boars, wolves, and bears. None of them had long-range attacks and weren't fast enough to obstruct Kai. One by one, they were cut down. Long range magical attacks seemed to be less effective than physical and close-range attacks so Kai continued slashing with his water sword.

But no matter how many he cut down, more replaced them. Soon, he was surrounded.

"[Compressed Water Whip]."

Kai spun while swinging his sword. The moment he spun it, the length increased and instead of a solid sword, it became loose and wave-like but the quality of the sword wasn't reduced in the least. All of the beasts that were hit put up no resistance and were cut apart.

The instant his attacks ended, the boars took the opportunity to leap over the dead bodies and charged at Kai from all directions. Kai jumped instead of using the same maneuver and stabbed out with a water sword.

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"[Sea Serpent Blade]!"

The sword burst and shot a huge snake head made of water which swallowed the boars whole and crushed them. Kai then moved his hand to which the head followed and every figure that was in its path was swallowed and crushed under the water pressure.

Then, Kai stopped. He stood still amidst the hundreds- no, thousands of corpses around him and then at the possibly hundreds of thousands of figures in the distance. He then snapped his fingers and the sun soon became covered in clouds and rain began to fall in large amounts. The beast-like figures who had none of the instincts of a normal animal didn't stop nor were they disoriented by the rain.

Cold air began to seep out of Kai as he raised his hands towards the sky.

"[Ice Domain]."

In an instant, the battlefield that was drenched in rain was covered in ice. The raindrops in the sky became beautiful snowflakes. Dozens of kilometers were covered in ice of varying sizes, any and all beasts in the area were frozen solid.

This was one of Kai's techniques that encompassed an insane range. Ice domain released a huge amount of cold air which mix with the ice, spreading more of the cold air. It would take time to spread on a normal surface but if the area is even a little wet, the speed it froze things became many times faster. Normally, to cover a distance of a dozen kilometers with this ice, Kai would take four or five seconds for the outskirts. But using the rain which encompassed an even larger area, Kai created a garden of ice.

There was a certain difference between those who use ice in this world and Kai and Erina's ice. The major difference is that those from this world could spread ice over a large area but it would take time while Kai and Erina could do it in an instant. This was because they understood the environment with modern knowledge. Air wasn't just comprised of gas, it also had moisture albeit a small amount. Using that, the cold air uses the normal air as a medium to travel faster.

It was like comparing a person's sprint to a sports car. Hyosuke had to resort to an underground water cave so that he could strike from the bottom but Kai and Erina could do that without any preparations.

Silence.

Kai couldn't hear any beasts near him, they were all frozen in ice. Those that were far away were having trouble getting over the thousands of frozen beasts which provided Kai a breather. But it was at that point that Kai's eyes became sharp and he leapt backwards. Dozens of arrows impaled the spot he had just stood on.

Kai looked up and saw human-like figures riding on top of flying beasts of varying looks. Kai stretched out his arms and a bow made from ice appeared. One shot, two shots, three shots, with each shot, a flying beast fell down along with the human figures riding them. Those that fell were completely free from harm and began attacking with melee weapons.

Once all of the beasts were shot down, there were a little over fifteen of the human-like figures charging towards him. These looked exactly like the ones he had fought in the arena.

Kai created a great sword made of ice on his right hand and a kite shield made of ice on his left. He charged forward using the kite shield and slammed into two of the figures, he then sliced with the great sword which sent the two figures flying but safe. They used the swords to block at the last second.

But that wasn't Kai's problem. The figures actually managed to land a hit on Kai's arm. This wouldn't normally have him flustered in the least but something was different, he couldn't heal the wounds.

"...Immortal Slaying Ki."

Kai clicked his tongue at the wound that showed no signs of healing and focused his eyes on the approaching enemies. He couldn't afford to get hit anymore. Immortal Slaying Ki was special, it used life force as a form of attack. Although tiny uses of it wouldn't damage the lifespan of a person because they would regain the lost life force after a bit of rest, using it in a large-scale attack was tantamount to committing suicide. It would reduce a person's lifespan greatly. If Kai could use it and imbued it into an attack like [Abyssal Wolf], he would either die instantly after the technique is released or die trying to imbue it.

Immortal Slaying Ki was dangerous, its strength was unfathomable, mana couldn't even hold a candle against it. But nobody can use such great power without a price. It was a requirement for Gods to learn this and the number of mortals that could use it probably didn't even amount to a handful. Even Kai couldn't use it, the amount of training required to control one's life force and convert it into energy was insane. Kai's rune training or any other form of training he had done was basically tutorial mode compared to it.

Kai's body was suddenly covered in armor.

"[Armor of the Frost Giants]."