I'd quite like to throw my hat in here as well. And as usual, I'm going to try and do something mortal-themed.
Name: Destiny/Variable
Spheres: Legend, Destiny, Fate
Personality/Traits: Variable. Personality follows whichever creature summoned Destiny's power. See notes. Its primary purpose is to create legend amongst the mortal races.
Appearance: Variable. The appearance of whichever creature is playing host. See notes.
Notes: "Destiny", for want of a better term, is a primal force of narrative and inspiration. It does not have a permanent form, or even a permanent character. It can be summoned by the prayer of a single mortal, which it will inhabit at the cost of the mortal's soul. It can only empower one mortal this way. Destiny lacks the more impressive powers of other deities and can only accomplish what is within the sphere of mortal power to achieve. Within such spheres, however, it is significantly more effective than usual for a deity (due to that 'personal touch'). Destined mortals can employ Destiny's innate power to gain significant influence over their fellows, usually rising to positions of power and influencing whole peoples (by which 'divine' acts are accomplished).
Destiny can sustain a mortal form for no longer than 3 turns (unless circumstances allow otherwise), at which point the mortal dies of old age or natural causes. Thereafter it must be summoned by a new mortal.