As a hero, he cannot be converted and can regenerate health (since The Conquerors). He has the appearance of a Paladin with similar stats but has higher melee armor and more hit points except if the player is using the Franks (which they are in the Joan of Arc campaign), in which case a regular Paladin has two more hit points. Also Guy Josselyne moves faster but attacks slower than Paladins. Technologies that benefit cavalry also benefit Josselyne, but he is not affected by civilization bonuses.
- If Josselyne is killed in the scenario A Perfect Martyr, his last words will be "It is here that my tale will end". However, when the player wins, Josselyne will still narrate the aftermath regardless if he survived or not.
- Josselyne was named after a French minor noble family in the family tree of ES lead designer, Sandy Petersen.
- Though fictional, Josselyne is loosely similar to Jean Poton de Xaintrailles (c. 1390 - October 7, 1461), one of Joan's most important supporters. Xaintrailles was a veteran of a catastrophic French defeat before meeting Joan (Verneuil); fought at Orleans, The Loire, and Compiegne; was promoted to Marshal of France in 1454, the year after the Battle of Castillon; and died in Bordeaux, also the final established location of Josselyne.