Fane's ancestors were originally of a house other than Jesamine, with which Jesamine was in a state of feud for some time. Ultimately, Jesamine got the upper hand and held it by enough of a margin to assure superiority, but not enough to insure against a fairly damaging war of attrition.
An unusual deal was struck upon, though the reasons for the opposing House's agreement were never made clear; Jesamine would absorb the lesser house by way of a marriage of law (no children would be had, by formal agreement), ending the feud. In turn, the lesser house would renounce its name and identity, and all its resources would become Jesamine resources. The only trace of identity left was the former Lord's name, Fane; the line descended from him has been termed 'Fane's line' ever since, the actual name of the defunct house stricken from all records, and in time, remembered only by a few.
Fane's line, from that turning forward, never did commingle with Jesamine blood, though they held the name Jesamine as legally as any other. Viewed as a second class within the house by the Elders, the Fanes simply adapted, taking up non-threatening administrative roles within the house, and the house's holdings out in the Black Zone. Each generation, the first son born to Fane's line took the name Fane, and so on, and so on, up to the present Fane (the fifth).
Following the death of Fane IV, the younger Fane was sent out to administrate a minor Black Zone shadow for a fairly long term (we'll leave that vague), as Jesamine's Legate (judge and ruler) there. The shadow itself had little intrinsic value beyond the fact that it was, indeed, Black Zone real-estate.
Several others of the line of Fane were sent on similar assignments, isolating the Fanes from the Chaos side of things. What the Elders had in mind with such a move is uncertain, though it's likely that they were insulating against the possibility of uprising by Fane's line.
Time passed, and, barely known to the Fanes in shadow, the younger generation of Jesamine proper took power in the house; and then took the throne of Chaos.
A time later, Fane V's term of service in the black zone came to an end; bringing us to the present.
As to the others of Fane's line, they are presently content to remain out in Shadow. To a one, they all still contend that it's much safer away from the center of things, and none would follow Fane back to Chaos, yet.
Fane is returning to a very different Jesamine than the one he knew when he left. He has the weight of that original experience (he was a few score years old at the time he left), plus an extended term tending to a Black Zone shadow and making the best of it.
He'll be interested in integrating into this new power structure and, if it seems to be better disposed to him and his line (all indications are that it will be), reinforcing that structure. In this, he may take on a role of instructor, mentor, or advisor, if others invite him to do so. This may also extend to protector, in a sense both military and political.
At the core, Fane has had the sense of artificiality passed down to him through the generations; he has not forgotten that his house isn't truly Jesamine. At the same time, Jesamine has done passing well by him so far, so long as he's minded his place, so he's in no rush to mar the status quo.
In the longest term, Fane wants to separate his line from Jesamine again and start his own house. As a player, I personally don't want ever to see this goal realized. I want it to be long term and in the distance, something which can be used to explain his short-term goals and motivations, something which produces those. To that extent I intend to intentionally limit myself: even if the circumstances 'seem right' for him starting a house of his own, he'll find some internal reason not to pursue that at that time ('No, I don't have a strong enough foundation yet. I need to strengthen X, Y, and Z, and attain Q, before I can push forward.') It is thus an implied condition of acceptance; if my application to be of Jesamine is approved, I will never undertake a 'splitting' action without the combined express approval of the entire House. Effective for the duration of the character's play on Amber, Fane is a Jesamine, and will remain a Jesamine.
So, in the short term, towards his ultimate distant and unattainable goal, Fane will:
How these actually translate into concrete attainables (Logrus is a too-easy example to give, but is there nonetheless) will depend on how his story unfolds in RP.
I want to stress that I'm fairly flexible. The main details I'm interested in for this character are a) a realistically extended drive toward achieving an independent house -- too many in Chaos try for this at an overaccelerated pace; if it's done properly, it should take years upon years (RL), and I intend to do it properly, and b) the sense that his bloodline's title is as much "bought" as it is hereditary, and c) the cosmetics of his appearance.