His wife is Adalfrid of Applestone. His son is Suitov Iceheart.
Steedfast's name in its original language is a play on two words meaning "dutiful plodding steed" and "snap decision-taking". Calling him 'Steedfast' in English is an attempt at an equivalent pun.
He acquires the nickname thanks to his first couple of victories in battle, which set the tone for the rest of the campaign: capability, a strict sense of honour and/or obligation, a lack of innovation and an ability to respond to changing events quickly.
Steedfast is notable for being a capable warlord in his younger years.
After peace breaks out he retires home with some relief, marries an apparently quite ordinary girl and has two children. His wife and the second child are killed in an accident, shortly after Steedfast's own death in more suspicious circumstances. The elder child becomes the next Suitov, in due course acquiring the name Iceheart.