Counterattack System appeared when I'm already At The Mahayana Realm - Chapter 543 - 545: 544: I’m a Middleman between Two Worlds

He said coolly: “One million a month, stay with me!” She raised her eyebrows and smiled: “Pay a 30% deposit first, no credit!” Show no mercy. When the contract expired, she turned around gracefully, and when he chased after her, she found that there was already a kid the size of a kid beside her…

- Description from novelbuddy

In a world where black holes, magical talents, and formidable hunters form the fabric of everyday life, Ethan Cross—a freshly graduated student with an uncertain future—once believed he would lead an ordinary existence like everyone else. However, everything changed when he awakened a seemingly feeble and inexplicable ability known as “Coexistence with Darkness.” No one took his talent seriously—until a catastrophic dimensional rupture unleashed terrifying creatures known as the “Demons of Corruption” upon him.On the brink of death, the pendant he had inherited from his father suddenly activated, summoning three dragon girls—beings of unimaginable power, yet with complex and rebellious personalities. Cursed in the past and trapped within that pendant, these three dragons have now become inexplicably bonded to Ethan. The twist, however, is that they neither recognize him as their master nor believe he is worthy of such a union.Now, Ethan must unravel the mystery of the darkness within him, learn to control his burgeoning powers, and find a way to tame these proud dragonesses—forces that could either aid him in his quest to conquer the underworld or lead to his ultimate downfall.A power that no one had believed in has become the key to mastering the shadows. Can Ethan harness it without being consumed by the darkness?

Jian Wushuang was reborn in adversity. In order to get his revenge, he began to cultivate Heavenly Creation Skill. With the help of the Heaven defying cultivation method, Jian Wushuang gradually grew into a peerless genius from an ordinary practitioner. With a sword in hand, no one is his match. Using his extraordinary Sword Principle, he killed all his opponents and eventually became number one Sword Master from time immemorial.

Another entry in what you can call the Proto Harem Series: the books written before the Harem Series that take place in the same world.

It’s about a swordswoman whose student is captured, so she goes to rescue her.