It's Hero Time! Vol 1 ( Ben 10 x Massive Harem)

Chapter 5.5 Dealing with some Punks

This story takes place after Moka's battle with Gin and before her confrontation with Miss Hitomi Ishigami. In this timeframe, Ben has given Moka the ability to switch between her Outer and Inner forms at will. However, she still enjoys it when Ben removes her rosary.

Ben and Kurumu found themselves in a fierce battle against the vile Nagare Kano, a twisted slug monster known for his insidious nature. With a grotesque, slimy exterior, Nagare used manipulation and blackmail to coerce Kurumu into compromising situations, threatening to reveal secrets that could shatter her reputation. This left her grappling with doubt about her friendships and feelings. However, Ben, determined and unwavering, unravelled the truth behind Nagare's despicable tactics. In a climactic showdown fueled by courage and camaraderie, Ben and Kurumu joined forces, combining their strengths to fiercely confront and ultimately overpower the grotesque creature, reclaiming Kurumu's dignity and solidifying their bond in the process.

His new form made Kurumu want Ben even more( she wants him to take her = sex)

After entering into a unique agreement with Kurumu, Ben acquires the powerful Incubus form. This transformation grants him enhanced abilities and attributes. With a newfound strength and agility, Ben takes his powers a step further by evolving into a new form known as Slugger. Slugger embodies a formidable presence, amplifying his combat skills and versatility in battle. For more intricate details on these transformations and their capabilities, be sure to check out the section on Ben's Aliens, where you can find comprehensive information about both Incubus and Slugger.

A few days later, Ben and Moka found themselves facing off against Junya Inui—a conniving Onimodoki who schemed to win Moka's friendship for his own gain. As the tension in the air thickened, Ben's instincts kicked in, and he quickly discerned that Junya was nothing more than a fraud, masquerading as a vampire to get close to Moka. When Junya lunged at Ben, his attack struck true, but Ben immediately felt the difference; Junya lacked the supernatural strength that radiated from Moka.

In a surge of fury, Moka released her inner self, transforming the atmosphere around them. In response to the escalating chaos, Ben morphed into Whampire, yet something about his appearance had changed. As the fight unfolded, Junya, with a sly grin, managed to seize Whampire's mask and deliver a forceful kick that sent him crashing against a sturdy tree, ripping the mask away and unveiling his true face.

When Whampire returned to the group, stunned silence enveloped them. The transformation had left him looking strikingly similar to inner Moka, his hair now a radiant shade of white, yet his vibrant green eyes remained unchanged. The shock was palpable as power emanated from him, and with swift precision, Whampire knocked Junya out cold. He then scanned the defeated Onimodoki, assessing the situation.

To add to the bewilderment of his companions, both Mokas felt a flutter of admiration for Whampire's new look, their cheeks flushing with unexpected warmth. His accent flowed like silk, leaving the Vampire girls blushing fiercely, captivated by this mesmerizing blend of power and allure.

Since Ben utilized the Omnitrix to scan Moka, Whampire has transformed into a Shinso vampire. However, it's worth noting that the process of becoming a Shinso typically requires an injection of Shinso blood, which raises questions about the nature of this transformation. Given that the Omnitrix is an advanced piece of alien technology, it's uncertain whether it could replicate the necessary conditions for such a mutation to occur. The mechanics of the Omnitrix might allow for unexpected outcomes, making Whampire's mutation a fascinating yet confusing development.