So if there's no demon lord or anything, why even bother sending out a hero running around?
Not to mention, this party lacks a tank and will go to shit the moment something bad happens. No Knight No Life (literally in this case)!
@Deathhappens
The summoners mention that. The hero party in a Demon Lordless world is basically just a celebrity group. They have social meets, sell souvenirs, that sort of crap. So a boy for girls to pine for, a girl for boys to love and the connected kid. There's really no reason to add any specific class to that since they won't fight any serious enemies anyway.