Io

 A large grin appeared on his face, followed by a chuckle of disbelief. This had better been worth it.

"Yes, make a contract with the Nightmare Bat."

[Contract established! You have 1 left.]

"Let's see this thing in action. Summon!"

 The ground immediately began to rumble, with black mist subsequently seeping from it. Dark particles, which had been previously invisible, then started gathering while forming various shapes, the likes of which Derrick recognized as dark bones, organs and flesh, their dance leading to the creation of something that looked more and more like the creature he'd just killed.

 When the process finally concluded, a shadowy monster was looking at him with its big, glowing red eyes, an impressive sight if not for it being so god-damn terrifying.

"Well, I guess this explains why everyone hates necromancers... This is enough to scare the shit out of people! I remember there also being a 10% overall boost when I summon, right? Show me its stats."

[Nightmare Bat]

[Strength: 4.4]

[Agility: 2.8]

[Endurance: 3.3]

[Vitality: 1.1]

[Magic Power: 1.1]

[Trait: Echolocation (Allows it to locate, without its vision, its prey).]

[Skills: None.]

"This is my first subordinate, and it's already pretty powerful. This should help me a lot. Now let's think of a name for you... How about Io?"

[Summon named successfully!]

With this out of the way, it was time to plan his next steps.

"Io, scan the cave with . We have to know how many of you there are out there."

[Echolocation in progress... 237 entities found!]

"What!?"

 Derrick was flabbergasted. How had life thrived so much in such a hostile environment?

"This system sure likes to make things difficult... It transports me somewhere unknown, gives me an unfamiliar body before finally making me fight monsters that are more than twice my strength... I guess it was the price to pay for getting all of this."

 Once he shook off his surprise, he continued.

"It's too bad that the bat fell at the bottom of the lake. I could have salvaged it for food, weapons, armor and clothes. This should definitely be my top priority going forward, meaning we'll need to find isolated beasts and hunt them down. We should also know our retreat route if things go awry. Io, find the exit."

[Scanning of the cave using ... 15%...33%...62%...87%...100%.]

 A map suddenly appeared in his consciousness, with the cave's layout defined by a thin yellow line and the monsters, by pulsating red markers.

"I really want to leave this forsaken place, so let's get started."

 But before Derrick started walking, his gaze locked onto Io, quickly realizing that the beast was now a bit bigger than its original form.

 Would it be possible to...?

"Io, can I ride you?"

 The creature looked like it understood his request, as it made a few disgruntled noises before lowering its wing.

"Wow, I didn't expect you to be able to fly with me! It's going to be a huge time saver."

 But after jumping on its back, he realized that it was easier said than done.

First, Io's back, despite being bigger, still wasn't large at all, making this an unstable mount at best. When also paired with the creature's weird and uncomfortable feathers, he could already tell this'd be troublesome.

"I'll certainly have to train to avoid accidents..."

 After settling as best he could, he then again analyzed the map which, after a few seconds, led him to his first target. It was farther away than expected, but the surroundings could be taken advantage of, making this a great opportunity.

 And as if reading his mind, Io didn't wait before taking flight, almost ejecting the new necromancer in the process.

Their journey had finally begun, although under a rain of curses as Derrick fought for his life...

***

"We're almost there and our prey is barely moving. Looks like I'm finally catching a break!"

 Derrick was rejoicing at the idea of a fast hunt. When done, he'd get out of this cave and explore this new region, an idea that thrilled him to no end.

 After fantasizing some more, he calmed himself and refocused. He couldn't mess up anymore, especially not when facing monsters that could tear him apart. Strangely, this realization didn't terrorize him, instead driving his blood to boil in anticipation.

 Was he really relishing these new and deathly challenges?

"We've arrived!"

 From his aerial vantage point, their hunting ground was a small valley filled with depressions and small boulders. At its center was also a small pond, which was presumably fed by the lake he had been in earlier.

"Let's be cautious and land further back. Getting discovered right away would negate our advantage."

 They then landed on a small hill overseeing the sector, allowing them to start looking for their prey. But even after a while, no movement had been discerned, prompting him to once again look at his map, the red mark still there and pulsing.

 Something wasn't adding up.

"System, use on this region."

[Using ...]

[Life Form detected! Dark Furcifer Pardalis.]

"Well, that explains why we can't see it!"

 When he was younger, he had read about species of reptiles that could adapt their camouflage to their environment, allowing them to simultaneously evade and hunt.

"Show me more."

[Dark Furcifer Pardalis]

[Strength: 3.5]

[Agility: 3.5]

[Endurance: 2.0]

[Vitality: 3.0]

[Magic Power: 3.0]

[Trait: Cold Blood (Allows it to lower its temperature to survive in different climates), Camouflage (Allows it to morph with its current environment), Tongue Lash (Allows it to snatch its prey at long distances).]

[Weakness: Sudden temperature changes.]

"Hmmm… It's definitely not an easy target, but we can succeed if we're careful. The problem is that the map's not precise enough, so we can't pinpoint its location."

 After a brief reflection, a mischievous smile appeared on Derrick's face, followed by him abandoning his cover and walking towards the valley.

"Io, hide in my shadow and be ready. It's time to set the bait."