Jakob is a hunter who Geralt comes across and eventually decides to travel with. He is kind and receptive to Geralt, despite being haunted by his dead wife. He's a middle aged man with (preferably) and Irish or English accent (feel free to experiment). Despite having tragically lost his wife, I don't imagine him as having a particularly gruff or downtrodden tone, I'd prefer something that is mature, yet welcoming and endearing.