Purples story: He was a Clone of Red impostor and because of this, He was bullied when he was younger and had to paint himself purple to fit in, it eventually dried so it became his skin, only then a tiny puddle of water did nothing, expect he had touched water many times causing it to finally wear off a little when red throwing him into water accidentally. (Due to purple being a clone of red, this is why he loves green.)
Sorry but I'm too lazy to make red vs clone riggy but it goes with red eventually grabbing clone riggy and jumping so far they travel through time for a split second causing old green and old red about to hold hands for the first time to fall over with purple funningly holding onto clone riggy causing purple to surprisingly be the one to make red dumb as he hit red right in the head accidentally. Red impostor eventually kicks clone riggy back to the graph paper dimension. With Purple being thrown up into the air and falls into a puddle of water with red showing beneth him. This will make sense on how its not blood when I make purples story. Purple eventually walks away.