You activated the Monster Device and selected your wolf in the screen of it, making the wolf disappear in a white shine just as Gwen's bat, after that you held the device pointing at you like Gwen to herself.
Your body started to shake a little, watching how your arms slowly grew grey fur with black claws replacing your nails, at the same time two pairs of nipples popped out from your chest below your breasts, your feet morphed into wolf paws with a little bit of fur even that your legs were still human, your ears turned into wolf ones, a not so long wolf tail appeared above your butt and your nose transformed into a snout. You finalized your transformation as a wolf woman hybrid, looking like an inferior version of the professor's wolf form as she had her wolf in their last evolution.
When you were transforming you also looked how Gwen's body changed, from her legs to her feet turned black skinned with dark blue fur as her feet turned into bat paws, her arms got thin as tree branches just for seconds later grew her dark blue bat wings on them, her ears lengthened a lot, her short black hair got longer covering her eyes that were red now, two of her upper teeth lengthened into fangs and a dark blue fur collar adorned her neck above her massive breasts.
"Hsssssss" Gwen creepily hissed licking her mouth lips with her big and long tongue. "You look very tasty Sally" she drooled.
Despite that was the first monster Gwen received she looked really powerful, maybe because her monster just had one evolution that would take a long time, making the battle look a little unfair, but you felt your tail wave at its own, feeling your wolf trusting you.
You quickly approached Gwen using all your four paws to sprint into her, but she instantly reacted using her wings to elevate her and dodge.
Then she aggressive tried to grab you with her feet, but you quickly grabbed her and knocked her into the floor, leaving her dizzy for a few seconds. You took advantage and put your face into her hairy pussy, licking it quickly to make her cum.
Gwen was just paralyzed in pleasure but didn't let that emotions to distract her for too much, she grabbed your shoulders with her feet and flipped you looking at the ceiling then she sat on your belly and looked at you, drooling and dropping her saliva in your face being unable to control her desires. You tried to push her back but her legs were to strong, as you struggled Gwen licked your ears and then giving you a deep kiss, feeling her tongue all inside your mouth and making your pussy extra wet.
"I knew you were tasty" Gwen said giving a creepy smile. "Now it's time to finish you!"
Before she acted you used your tail and wrapped her belly to push her backwards, falling into the floor again. Now you used many of your fingers to masturbate her.
"N-ngh... N-no!" Gwen moaned as her nipples erected.
You pushed your fingers harder inside her, Gwen tried to move but paralyzed in pleasure again, squirting over all the floor and losing the battle.
You stood up and used the device again on you, making all of your wolf attributes disappear and looked your wolf return next to your feet. Gwen did the same and returned to her human self with her bat tired sleeping on her belly.
"Bravo!" The professor clapped, "you two seem to dominate the monster fusion and its combat, now get ready to explore the world and become a professional monster trainer!"
"Ugh, whatever..." Gwen stood up, "let's go buddy, the next time we will defeat her for sure" she spoke to her monster and exited the laboratory.
Now that you had the professor approval, you exited the lab too and saw all the world you had to explore.