Hjalmar is the son of Crach an Craite. He was in love with Ciri. His nickname in Polish is "Krzywogębym", which seems to translate to "slackjaw".
Στο παιχνίδι για υπολογιστή The Witcher 3: Wild Hunt
Hjalmar is set to appear in the upcoming final chapter of the Witcher game trilogy.