Naruto: Is it template system or harem system?

Kai woke up in the Naruto world, but he wasn't a hero. He was just a regular Uchiha, stuck in the middle of a huge war. The Fourth Hokage was about to arrive, and things were getting dangerous. Suddenly, a voice boomed in his head, "Ding! One-Click Max Level System activated!" Kai was confused, but then he realized he could learn any jutsu he wanted, instantly! "Great Fireball Technique? Done! Max level!" He blasted a giant fireball with ease. "Shadow Clones? Done! Max level!" He was surrounded by dozens of his own copies. "Sharingan? Done! Max level!" He could see everything in slow motion, and his eyes glowed with power. "Sage Mode? Only one in ten thousand can learn it? Done! Max level!" Kai was unstoppable. He could learn any jutsu, no matter how difficult. The war was about to get a whole lot more interesting.

Ryuji a normal guy from Earth, traveled in the world of Demon Slayer, equipped with Hyper-Dimensional System. In his first day he was given a contract with a demon spirit. [Starting Bonus Issued: Demon Slayer Sword x1; Demon Spirit Contract Signed, Obtaining Demon Spirit Devourer] His abilities allow him to consume demons, opening up the path filled with possibilities and challenges for him.

Transmigrated into the Bleach world, becoming Shunsui Sakuranosuke Jirō Kyōraku's nephew, Kyōraku Callum, bound to a check-in system. Checking in allows him to grow stronger, and he even obtained a unique time-type Zanpakutō. Time Rewind, Time Stop, Time-Line Severing However, in the perilous world of Soul Society, for his own safety and survival, he resolutely chose to join the Fourth Division.

Uchiha Kaoru!!! After transmigrating into a member of the Uchiha clan, I discovered that my Sharingan could use skills from League of Legends. For medical ninjutsu, I have Soraka's skills! For genjutsu, I have Shaco's fear! For taijutsu, I have Lee Sin's "Iku"! Ninjutsu is even easier; with over a hundred heroes, I will have over a hundred kinds of hero-based ninjutsu!

WARNING: MATURE CONTENT (18+) Area reached the top floor by elevator, and as she opened the heavy door of that vast boardroom, her breath stopped. Liam was not alone there. Seated around the massive table in the room were Liam's four older brothers Adrian, Cael, Xavier, and Ethan. The deep, intense gazes of these five powerful and influential men fixed directly on Area standing at the door. The eldest brother, Adrian, stepped forward, gestured toward a chair, and said with utmost courtesy, "Please sit, Miss Area. Liam told us everything about last night's incident and your mother. You are completely safe here, so please don't be afraid."

No need to invite me, I've already transmigrated. I've arrived in a world where only madmen can survive, yet I possess the Ninja World System from Naruto: How will I manage to live on? Will he become a madman and go insane alongside a group of cursed spirits, or does he simply wish to live as an ordinary person?

Ah! Reincarnation! A second chance at life, it's a perfect opportunity isn't it? Wrong Between a disability that makes him so weak that his parents want to abandon him in the street, a war building up, and not even knowing which world he's in, Jeremy would say you're wrong. Reincarnating is an horrible experience. And he STILL doesn't know in which world he's in! _______ Kiiiind of slow burn, of course in the world of naruto but the protagonist will take some time to figure that out. Pretty dark too. Doing this story to train my writing. _____ Also on royal road

Gate Vladimir has a unique ability: The Fantasy Gene. Fueled by mysterious energy, he can transform into iconic characters from various fictional works, such as Bleach's Sosuke Aizen, the Lich King, Madara Uchiha, Artoria Pendragon, Archangel, Ainz Ooal Gown, and Deathwing. This power allows him to become the ultimate one-man pirate crew, that even Whitebeard declares, "This era is called 'Gate'!"

When Harry Potter, Master of Death, is unexpectedly transported to the Marvel universe, he finds himself grappling with a new set of challenges. Haunted by the traumas of his past and the scars of war, Harry must navigate this unfamiliar world. Harry x Natasha, Harry x Sif

Reborn...The first world is Hunter x Hunter.What Oboro didn't expect was that the first character he encountered was the one with various famous names like madman, fruit farmer... Hisoka! Fortunately, he has an AI system as his intelligent artificial assistant. Oboro says: "No matter who it is, as an omniscient transmigrator, I will show you what it's like to develop Nen to the extreme...