A bit too high-tech for what I had in mind, although we might be able to tweak it into something similar but magical rather than technological. Elven illusionist/summoner, alienated from his native society as an aesthetic and cultural misfit?
Most of the world is late-medieval; small parts are early-Renaissance, other bits are Bronze age to Stone age. No electronics, no steam engines, no gunpowder, minimal clockwork. There are parts of the world in which magic supplants technology to a significant degree, however.
To give an idea of the cultural background:
The magical catastrophe known as the Banestorm brought countless amounts of people and creatures to Yrth, including humans from Medieval Earth. And as humans tend to do, they soon expanded to take over most of the continent of Ytarria, displacing the native elves and orcs (the dwarves remained safe in their mountain fortresses). One thousand years later, Ytarria is dominated by the East-Coast Empire of Megalos (Catholic, powerful, sorcerous, old and corrupt), surrounded by various nations on all other sides. A significant minority of the Megalan population are goblins, of the green-skinned small-but-clever trickster variety.
South of Megalos lies the independent country of Cardiel (probably the most cosmopolitan society of Ytarria; as well as a nearly 50/50 Catholic/Muslim population, they also have small groups of centaurs and halflings and are one of the only places in Ytarria with openly Huguenot communities). Cardiel was formerly a Megalan province, and before that it was the mixed Islamic nation of al-Kard. West of Cardiel are the Sunnis of al-Wazif (ruled by a Caliph, and tolerant of magic: think Arabian Nights) and the Shiites of al-Haz (the nation guarding the Holy City of Geb-al-Din, controlled by the clergy, and intolerant of magic: think Saudi Arabia).
Technology in Megalos and the Islamic nations is medieval, while the semi-autonomous Megalan archipelago of Araterre in the far South is slightly more advanced (swashbucklers and foppish nobles duelling with fencing weapons, but still no gunpowder). Nearby is Bilit Island; Aztec society crossed with a Sinbad ecosystem. The Nomad Lands to the North of Megalos (Celt/Viking/Mongol: "barbarians" of all sorts) are closer to a Late Iron Age tech level.
West of Megalos is another ex-province, now the country of Caithness, where an unusual local interference with magic defends it against Megalan reconquest (and provides for a more Arthurian ambience than the magically-saturated Megalan culture). South of Caithness is the elf-infested Great Forest, while the mountains to the North hold the dwarf nation of Zarak. Further West the lizardmen of the Great Desert provide a buffer against the tribes of the Orclands on the west coast.
The nations of Ytarria are mostly at peace, but the last Megalan crusade was less than two decades ago, and a civil war has wracked Caithness for years.
Races available are humans (from assorted cultures and religions, ranging from stone age to early Renaissance), elves/dwarves/halflings (all fairly Tolkeinesque; elves are aloof and innately magical, dwarves are miners and tough fighters, halflings are good sneaks), goblins (similar to humans, but a bit smaller, trickier and more prone to magic), gnomes (kind of above-ground dwarves, not as militaristic), orcs (barbarian bad guys, killed on sight in most human lands), ogres (bigger dumber orcs, occasionally used as slave-soldiers in human armies) and reptile men (big and tough but also mostly seen as kill-on-sight monsters).
The campaign would be starting in Cardiel, one of the more cosmopolitan and tolerant of the human nations. Humans or goblins of any culture would fit there, as would elves/dwarves/halflings/gnomes. An orc might get away with it if they're careful to keep their identity hidden; ogres or reptile men are in trouble unless they're part of a powerful noble's bodyguard or somesuch.