if you get the sword which kills dethrel,the demon south of varrock, go to the wild and go kill lots of demons, coz the thing is it works on normal demons too, so if i had a lvl 6 account i could do the dethrel quest, have the sword then go kill demons and get as much cash as i want and they drop rune itiems like rune kite,rune plate and rune helmet. So get out there and fight demons!