
You seem to have already spelled out your answer.
 If you haven't established him as being an expert at it yet, then traditional study and training will take him years if you treat it realistically (and that's assuming he can endure and pass said training). The only quick route is a soulstone, and given how much death there's been recently in the liberation of Othard (and then said Othardians going temporarily to help liberate Ala Mhigo), it's not unreasonable that he could've found a soulstone - and, that a teacher who has lost many pupils would be willing to show him the ropes in an accelerated manner by making use of it.

Lydia Lightfoot ~ The Reliquarian's Guild «Relic» ~ Lavender Beds, Ward 12, #41
This player has a sense of humor. If the content of the post suggests otherwise, please err on the side of amusement and friendship, because that's almost certainly the intent. We're all on the same team: Team Roleplayer! Have a smile, have a chuckle, and have a slice of pie. Isn't pie great?
This player has a sense of humor. If the content of the post suggests otherwise, please err on the side of amusement and friendship, because that's almost certainly the intent. We're all on the same team: Team Roleplayer! Have a smile, have a chuckle, and have a slice of pie. Isn't pie great?