A spoiler is a piece of information about a narrative work which reveals plot points or twists and thus may degrade the experience of persons who wish to experience the work themselves.
Spoilers on Inkipedia
Aside from leaks and future content, Inkipedia has no restrictions or warnings whatsoever on content that might be considered a spoiler, so you might encounter some information regarding Splatoon that you did not want to see. If you find yourself in this situation, discontinue viewing Inkipedia immediately.
Inkipedia is only here to provide information. How and when you read that information is up to you, so Inkipedia cannot be held responsible if your enjoyment of a game is impacted due to reading spoiler content.
Proceeding with caution
If you have not completed the story, but decide to read Inkipedia articles for other information, be mindful of the article title and section title, as these are good indicators of what you will be reading. Article sections like "Summary" or "Plot" or "Story", and articles dedicated to characters, are likely to contain story details.