A standard game implies 4 Mafia (or opposing team) and 1 Independent. Whether that independent in a survivor, a serial killer, an arsonist or werewolf depends. I don't know AoT much to know if there is any corresponding or fitting character for these roles.
Let's also not analyze every statement made early in the game—a lot of us are new and just chattering about. I don't take Ha0's statements about murdering Lanji too seriously.
Role Madness also means each and every member of the Town has a power role or function. It's important to stress some members of the town have investigation prowess. I.E., they can look at roles, look at actions taken at night, or simply see who you visit. The Investigation roles are pretty versatile and powerful, but also relies on good reads to really be effective.
If anyone happens to be a killing role for the town, I'd suggest they wait before acting. No need to be willy nilly and shoot anyone.