I've had in mind for a time a similar concept:
a very, very old swordmaster, who made a vow to defend his birth village until his death.
Funny thing though, he already died 3-4 times! When he dies, the villagers burry him in a nice tomb under the river and all pitch in together for the appropriate anti-necromancy, anti-decay magical protection.
Then, when the village is again in danger, the local priest resurrect him for free (you'll see) and there goes again our hero, fighting to save his hometown until he falls once again.
He's a good guy with a big heart, but a little cranky and...well...he suffers a little of the fact that the world changes a lot between each time he is awakened. He can be a little dephased each time, and tends to confuse the ''rules and standards'' of each generations and the historical fact.
On the PC sheet:
Human, Zealot barb (for the free resurrect!)
high Con, Dex and either Int or Wis.
Sage background
Sword and shield, armorless, an old straw hat