Don't rush yet to complete it. There is going to be a seasonal challenge next week that requires guardians to kill 10 ruffians. And it rewards repute, which makes it mandatory if you want to complete the seasonal seal. Funny thing is that they pair the requirement of killing 10 ruffians with a requirement of gathering 50 treasures. This is true PvP. You play against other people on your squad: https://www.light.gg/db/legend/3443694067/seasonal-challenges/2010547030/weekly/1911772883/week-9/