The following are the recommendations of a few completed system invincible check-in novels:
1. [I'm Unrivalled in the Martial Arts Library] by Mu Yi, who started a fire. The story described how Ye Xiao transmigrated to a parallel world, became an administrator in the martial arts library, and obtained the check-in system. He could gradually become stronger by signing in and collecting cultivation techniques.
2. "The beginning of the Immortal Cultivation signing Wu Song to fight the tiger" Author: There is a skill to watch the water. The story told the story of the Blue Planet's collective transmigration and entering various dungeons to seize resources.
3. "Sign in to the Sacred Body of the Ancients at the beginning of the game" by God J. Jun Xiaoyao traveled through the fantasy world and became the divine son of an ancient family. He had an invincible background and a check-in system.
4. [Invincible Style of Getting Reward at the Beginning] Author: Unknown. The protagonist in the story received various rewards by signing in and gradually became invincible.
5. " I Have a Check In System " by Linjiang Tingxue. The story was about how Liu Tian used the check-in system to increase his cultivation level every day and eventually became invincible.
These novels had all been completed and could be read on the corresponding websites.
The following are a few recommended killer novels, and these novels have all been completed:
1. " The Strongest Assassin System ": The protagonist of this novel is Twain. He transmigrated to another world to become an assassin and has the talent to become the strongest assassin. The plot was compact, and the main character's strength gradually increased. It was filled with a sense of humor.
2. " I Become Stronger When I'm Strangely Attacked ": This novel tells the story of an ordinary person who is suddenly bound by a system and becomes stronger through a strange attack to bring him a wonderful life.
Please note that the novels recommended above are based on the search results provided. The specific content and quality may require further review and evaluation.