The bloodmancer didn't need the other party to jump in a surprise. He didn't need the cloaked man to start looking around or prickling his ears either.
All Leon needed to realize the harsh truth was to see the man suddenly change his behavior.
And yet...
While the cloaked man continued to play his sneaky game of taking his time to mention Leon's presence... The bloodmancer didn't waste his time.
Ever since the man made himself known and brought the bloodmancer to an edge, Leon took his sweet time to pull out the bone pieces he obtained from the beast in the forest.
By the time Leon realized the other party grew aware of his presence, he already had both the bones and his spear in his hand.
'I hope your teachings will work in this world too, old man,' Leon thought. He then began manipulating his spear to carve small arrays of tiny symbols on each of the bones. 'Because it's time for me to get slightly more serious now.'
The idea behind magical engineering was perfectly simple. Back in Leon's homeworld, one had to reach the pinnacle of this school of magic to turn it into a useful ability.
But in this world... all the processes that turned the early stages of the magic engineering desolate have yet to take place.
'The difference between engineering and other school comes with how personal magic uses intent while engineering magic uses flow. ,' Leon thought, splitting his attention between his carving and the events playing out nearby.
And soon...
'He noticed me.'
It was high time for Leon to take action even if the other party had yet to act.
But Leon, immersed in the fun of putting the formerly desolate knowledge into use, couldn't stop himself from carving even more.
Then, the cloaked man started to speak.
'I guess that's time for me,' Leon realized.
He then took a deep breath before pushing the tiniest bit of mana into the runes carved out into the bones in his possession. And soon, he could feel the heat starting to come out of the tiny cubes he carved the bones into.
'Just like I thought.' Leon smiled inwardly.
The fact that the bone pieces started to heat up... meant that even if the mana in the air wasn't in a usable state for him... its flow could still power up the runes!
"Go and kill the rat!" the cloaked man finally gave his order.
'Damn,' Leon thought, tightening his grip over all the bones he managed to carve up so far.
Brought together, the flow that each of the bones affected would mix together and combine, accelerating the process imprinted upon the bones all at once.
And then, once Leon could feel the mana starting to act up around him, he made his first rapid move since he laid down and started to crawl forward.
He raised his hand, and threw the bones ahead, scattering them all over the camp.
"A rat?" one of the men asked. "You want us to hunt rodents now?" He proved his lack of situational awareness right away.
"You damn idiot!" the girl of the group put on an ugly expression on her face as she brought a bow down from her back and notched an arrow on its string. "There is an uninvited guest somewhere nearby!"
The girl turned around... and finally put herself in a position that revealed her pointy ears.
Leon, rather than on an arrow that she was ready to shoot at a moment's notice, focused on the peculiar feature of the girl's ears.
'An elf?' he raised his eyebrows in surprise.
BOOM!
Before Leon could think about this unexpected encounter for even a second, all the bones he carved out started to explode.
The formation imprinted on them was extremely simple, limited in its structure by the little time Leon had to whip some arrays out.
All in all, they were the perfect example of a positive feedback loop, focused on just three things.
Attracting the flow of mana, accelerating it, and then repeating the process.
The trick lay with how shallow the runes responsible for the last task were. When the flow grew to the point where the heat it generated melted down and erased the last set of runes...
Boom, boom, bo-boom!
More and more of the runes started to come off. There was no rule as to which bone would explode next, quickly turning the entire clearing into a modern warfare scene with explosives going off all around the place.
"Where...?!" one of the men shouted, jumping to the back...
Only to end up having his back charred by a bone that exploded behind him.
The explosions themselves weren't all that threatening. They were shocking for someone not expecting them... but offered little to no damaging power.
That is, a single bone would. And now that an entire set of them started to go off in every direction, their power combined and washed over the entire clearing, turning into one powerful shockwave!
"Fuck!" the cloak-clad man reacted second, jumping to the side, in the only direction that allowed him to avoid most of the impact.
'So he can detect mana,' Leon thought, observing the situation from his hiding place that was actually all out in the open. 'Or he is just insanely lucky,' he cursed, only to bury his head into the ground when the shockwave reached his position.
Contrary to the others, Leon was lying down. As such, the blast only tickled his back before washing over it and rushing towards the line of the trees nearby.
"Where the hell is he?!" the girl shouted, quickly regaining her composition and fixing her hold over both her bow and arrow.
Yet, in her mad desire to find out the one responsible for the explosions, she turned just a tad too quickly.
'Now,' Leon's entire inner self screamed out.
And right as the elven girl showed the bloodmancer her back, he jumped up, leaping forth in the direction of adventurers!