there are 9 broken idols and you need 5 people to do the boss in order for him to be in yellow you need to have repaired 9*5=45 idols, now this you can do it yourself, just need to have 45 idols in total, you can repair all the 9 idols 5 times to have de 45 and that will make him appear yellow every time if you are with someone else then you can split the number since the idols need to be in total of the team not the person