Yeah splatoon gore is sadly kinda rare, but then again can be kinda pointless considering they are made of ink. They do not have blood only ink, can reform at any spawn point, no bones to break, and are probably resistant to stabbing or piercing type weapons like guns or knifes. Which is why most splatoon gore is by people who know little about the game. But the potential is there; they melt in water, experience death on a regular basis, and explode when exposed to enough ink not their color.

Try searching on pixiv using the tags "R-18G" and "スプラトゥーン"