Wattson debuts in Chapter 203.
He and Coil-Boy have built robots to try and catch a rogue Donphan that has been pestering people around Mauville City. They accidentally catch Sapphire instead, but she reveals to them that she has stumbled across the entrance to New Mauville.Sapphire shows them the entrance. At that moment, a group of kids run up, challenging Wattson to a battle. They lose easily, but Wattson is impressed and touched by their enthusiasm and gives them all badges. He offers one to Sapphire as well because she found New Mauville, but Sapphire is insulted that he would give her a badge without winning a battle. She slaps his hand away; unfortunately, the badge in Wattson's palm flies off and hits the rogue Donphan, angering him, and he chases them. The three of them fall into New Mauville and Wattson is separated from the other two, stuck to a haywire generator. Shouting to each other in the dark, he and Sapphire make a deal: if she can help him solve the mystery of New Mauville, he'll have a gym battle with her.
He is very jovial.
The author describes him: "An expert of electric-type Pokémon, his true prowess is unknown. However, he is definitely not just an uncle who likes to joke. One who loves his city and children, he certainly will not tolerate the presence of the evil forces!"
Wattson and Coil-Boy are good friends; Coil-Boy even calls Wattson "Watt-Boy."