Shadow of the Valley by Disguise of Carnivorism is an AU next gen Death Note fanfic. Many years have passed since Light won out against all who challenged him and he is still working towards creating his utopia. Only Light isn't God, he is mortal and is beginning to feel his age... Fearing all his work will be undone upon his death, Light begins to train his heir to take over for him as Kira, and this sacred duty can only be entrusted to his own flesh and blood...
Warning! Spoilers for the series are unmarked.
Shadow of the Valley provides examples of:
- Abusive Parents: Light isn't really a good father to his daughter. He's extremely controlling of what the outcome of her life will be (ie. Becoming his successor), forced her to kill at a young age, deprives her of love and affection, and subjected her to horrific Training from Hell that reenacts all of L's investigations into him.
- The Aloner: Light. He spends most of his time now in the graveyard talking to his favorite victims. Hikari too because her father doesn't let her out much.
- Alternate Universe Fic: Unlike canon, Light succeeds in wiping out all who opposed him and continues his work in killing criminals as the god of the new world.
- Apocalypse Maiden: An implied case due to the ending being ambiguous on whether or not Hikari will continue her father's work, but she's raised as one who will wipe out countless lives with the Death Note as the successor to Kira.
- Children Forced to Kill: Light forces Hikari to follow in his footsteps, which includes forcing her to use the Death Note to kill people as soon as she's twelve years old.
- Chronic Backstabbing Disorder: Hikari notes how Light and Ryuk have several inside jokes about all the people Light has betrayed.
- Cool Old Guy: Light is still awesome even as a broken old man. Being in absolute control of the world and having outwitted everyone, including L and Near, adds to this.
- The Corrupter: Light makes sure that his daughter has no one but him and influences her to be the next Kira, which involves killing any who oppose her.
- Downer Ending: Hikari successfully kills Light at the end of the story. However, the Ambiguous Ending leaves it unclear whether or not she will pick up the mantle as the next Kira, but neither outcome is in the world's favor. Either she does and countless more will die, or she doesn't and crimes rates spring back up and countless people die.
- Grave Robbing: Robbers harvest something from the corpses of Kira's victims to make drugs. Kira himself (who is only known as the crazy guy in the graveyard) tries to discourage them.
- Kid Fic: A very dark version of this. The main focus of the fic is Light raising his daughter, but he's raising her to be the next Kira and ensure that she will become just like him; a ruthless, cold-blooded, manipulative killer.
- Oedipus Complex: Played with. Hikari attempts to seduce her own father, but it's not really out of genuine attraction to him. She's just so desperate for some form of love and affection from her father that she'd take romantic or sexual love over nothing.Light: Hikari are you trying to seduce me?
- Older Than They Look: Light ages quite gracefully and still looks much like he did when he was twenty but he feels worn out and used up from the subconscious burden of guilt of having ended so many lives.
- Original Character: Hikari Yagami, Light and Misa's only child. Named Hikari (Japanese for light) by Misa, much to Light's annoyance and discomfort.
- Pater Familicide: Light in order to "protect" Hikari from becoming soft kills off the rest of his family.
- Retired Monster: Light seems to have matured beyond his A God Am I kick and come to realize he's not going to last forever and if he doesn't want all of his work undone he needs a successor.
- Shout-Out: Light refers to L's grave as the resting place of The Once and Future King.
- Sibling Rivalry: This is why Light decides to bet it all on Hikari and not have any more children- because (in this universe) Sibling Rivalry destroyed L's successors.
- Succession Crisis: Part of why Light puts so much focus on training Hikari is that he wants to avoid this trope. He notes that L's legacy was brought to waste by in-fighting between his potential successors, Near and Mellow. Rather than risk that, he decides to bet everything on his only daughter.
- Training from Hell: Hikari is subjected to this, part of which includes Light reenacting his confinement in the form of roleplay games where Light plays the part of L and Hikari is suspect Kira.
- Tyke-Bomb: Hikari. Light makes her start killing criminals when she's twelve.
- Villainous BSoD: Light has one when he sees a grave robber defacing L's grave. Though this reaction was likely helped along by already being under the notebook's control.
- Worthy Opponent: Light laments that out of everyone he knew L would have made the best heir for Kira. If only he didn't oppose him, the transition would have been seamless...