Kakashi Hatake is often a popular character in these fanfictions. Given his skills and his experience as a ninja, he can be a very interesting ANBU Sensei. His Sharingan ability also adds an extra layer of intrigue to the training scenarios he can create for his students.
Itachi Uchiha is another one. His complex character and his skills as an ANBU member himself make him a great candidate to be an ANBU Sensei in fanfictions. He can pass on his knowledge of the Uchiha techniques and also his insights on how to deal with the darker aspects of being a ninja.
Sometimes, characters like Jiraiya also appear as ANBU Sensei in fanfictions. His vast knowledge of ninjutsu and his unique personality can lead to some really fun and educational training sessions for the ANBU recruits in the stories.
Chapter 114, "New House, New Rules, New Beginning [Four-in-One Mega Chapter]", is the clearest early answer because it turns Xia Chuan's situation into a concrete plot event. The chapter gives readers a real answer by opening on This new regulation, generally speaking, currently targets only the... and ending on Going out once every night earns one Contribution Point; bringing....
Chapter 158, "Preparation, Arrival", is the clearest early answer because it turns Great Xia's situation into a concrete plot event. Early on, First Year of the Great Xia, March 16th, around midnight The mine on.... By the end, If not for the special methods of the leader, who could convert....
Chapter 234, "Probing, Arrangements, and Hou Hu’s Confidence (Part 2)", is the clearest early answer because it turns Hou Hu's situation into a concrete plot event. It opens with Xia Hong had just swept his gaze over the people in the hall when Hou... and closes on If Hou Hu wasn't wary of him at all, that would be strange..
Chapter 185, "New Home, Land, Arrow Bamboo Forest", is the clearest early answer because the buildup finally cashes out in a real clash. It opens with And the grand golden chair on the high platform added a touch of... and closes on Anyone who came in saw Xia Chuan standing above the second-floor....
Chapter 231, "Investigating Yang Lu by Day—Whose Side Are We On?", is the clearest early answer because it turns Cold Resistance Level's situation into a concrete plot event. The chapter turns that into something concrete by moving from Except for Long Mountain, there are no more tall mountains on the... to This is considered Yang Lu's only strength..
Chapter 135, "The Fearless Mirror Immortal [Three in One]", is the clearest early answer because it turns Snow Mane's situation into a concrete plot event. The chapter gives readers a real answer by opening on Snow Mane could pretend to be dead, and pretend it did well. and ending on The environment here was evidently much quieter than outside..
Chapter 215, "Teaching Luo Cheng Techniques, News of the Jade Bone", is the clearest early answer because Li Baihe gets a payoff that changes the stakes. It opens with Did I get the address wrong? and closes on Though he had a Cold Resistance Level cultivation, he still needed to.... The key payoff is that the chapter exposes hidden motives around Li Baihe, so readers can finally see how the conspiracy layer of the plot is actually moving.
Chapter 189, "The Provoked Xiao Hen, New House, Xia Li", is the clearest early answer because it turns Xiao Lin's situation into a concrete plot event. Early on, The First Year of the Great Xia, Fifth day of the fifth month "A new.... By the end, Especially in recent days, with father and Uncle Yuan spending....
Chapter 145, "Murder, Gruesome", is the clearest early answer because it turns Vermilion Frosts's situation into a concrete plot event. The setup is A giant tree, over eight meters in diameter, came crashing down., but the pressure keeps building through Xu An rubbed his sore arms, looking at the many large trees that had....
Chapter 191, "Repel the Enemy and Punish, The 1st Wedding", is the clearest early answer because it turns Xia Hong's situation into a concrete plot event. It opens with From the north, a fierce wind swept in. and closes on They couldn't catch Chen Yingyuan's body, only the pervasive snow....