Devoted and loyal to his king, he will follow Barnabas's every command without question, proving himself a capable but ruthless Lord Commander of Waloed's armies. Barnabas even trusts him enough to speak for him in certain meetings, knowing the intent and feeling of his king on the matter.
He can also be rather smug and manipulative towards allies, as he mocked Hugo Kupka's defeat at Clive's hand that cost him his own hands.
Joshua concludes that Sleipnir is no man but a being formed by magic.