For starters, what is a “factotum”?
It is a latin word. Literally, it would mean (to) do [fac] everything [totum]. People who did all sorts of jobs could be called in that way.
And what has this to do with this game? Well, nothing, since it doesn’t exist yet. But it could.
A Factotum would be different from normal classes - mainly because it wouldn’t be a class in itself.
Rather, it is a way for a character to use all and only the four base classes, triggered by some (hidden) quest.
A Factotum would be able to freely choose one of the four base classes to advance at every rank (but still retaining the “three circles” limitation, of course). It would also retain the ability of purchasing attributes from the relative masters.
In addition to those, the Factotum master itself could sell additional, special attributes to add synergies within the different skills of the classes and give several bonuses (so that it can be balanced properly even in the later levels, despite being made only of the first tier of classes).
In a way, it would resemble a sort of “super novice” of RO, albeit in a way that makes use of the particular rank system of ToS.
It isn’t supposed to be some competitive character, but rather just a fun one, made for people that just want to do a bit of everything.