And then he can begin inquiring into their true names. It seems just crazy enough to be true and if it is true, does one lead them or are they more of a cohesive unit? Let's say they do have a leader and there is one Joker that reigns supreme.
Many comics have said that Sans is the older brother... But I haven't gotten any proof yet. It makes sense that Sans could be the older brother... But it makes just as much sense that Papyrus could be the older brother.
The brother of Papyrus, Sans first appears in Snowdin Forest, outside his hometown of Snowdin. The Snowdin shopkeeper says that he and his brother 'just showed up one day'. He works as a sentry at several posts in the Underground.