Guardian Louds is a Loud House fanfic written by The Loud Author, who also wrote A Brother's Debt.
When monsters begin to appear in Royal Woods, and begin wreaking havoc in an attempt to steal human essence through any means necessary, Lincoln and Lisa find themselves left with the guardian project, to make sure their family would not be hurt and to protect as many as plausible in Royal Woods.
It can be read here. There's also a prequel called "Guardian Tales: Ronnie Anne", which can be read here.
Note: Due to the sheer size of the fic, it's very likely you may come across spoilers, so read at your own discretion.
This story has examples of the next tropes:
- Affectionate Parody: Of the Super Sentai franchise.
- Doorstopper: Over 100 chapters, over 200000 words. Have fun.
- Heroes Prefer Swords: Lori does, anyway.
- I Gave My Word: Lincoln promised Ronnie Anne that he would let her take care of herself. Alas, this doesn't last, and the two break up over it.
- Superhero: This is what the Guardian Project turns Lincoln and some of his sisters into.