User blog comment:Swampman/SPOILERS----- Arisen Timeline/Speculation/@comment-75.112.131.72-20120704162357

I dont think Savan was the last one to kill the dragon and heres just one reason why: when an arisen kills the dragon they go to the everfall to open the portal to face the seneschal. When an arisen dies in the everfall their main pawn stays there wandering the everfall (for all time) or carrying out the final order of their master as seen in Quince and the three everfall merchants (who are pawns commanded to stay and be merchants to other arisen). Pawns do not return to the rift if they are masterless and wandering the everfall; Quince says she has been there carrying out her masters wish ever since she died. So the point is (finally) if Quince's master got to the everfall then she killed the dragon but never saw the seneschal (Savan) and Quince stayed in the everfall ever since, so since Savan summoned Quince from the rift before he killed the dragon then Quince's master must not have died in the everfall yet meaning she killed the dragon after Savan.

This means that potentially Savan could have been seneschal for a very very long time since we cannot base the timeline of his reign as seneschall on the number of hearts contained within Grigori (4 or 5?).