Childerich is the brother of Karl der Krumme, Lothair III and Ludwig der Listige. He is the youngest of the four brothers. His father died prior to the events of the questline, so he fought with his brothers over the kingdom.
Ragu describes him in the Scout Around quest as, "more interested in wine and women than in politics," and this is shown from the province dialogues, where he shows no interest in war and prefers partying instead.
After defeating Lothair III, the player would have to choose between Childerich and Karl der Krumme, who are currently fighting each other. If the player chooses to side with Karl, they would defeat Childerich. However, if they chose to side with Childerich, the player would still have to take over Mons Suiry in order to take reach Moravaria.
His first name seems to be an anglicization of the name "Childeric." If this were the case, then "Childeric I," "Childeric II," and "Childeric III" would all have been his ancestors. This theory is further confirmed by the fact that all of these were real-life Frankish kings, but "Childeric IV" does not exist.
The Story of the four brothers reflects actual history and custom under the Frankish Empire. Charlemagne had one son when he died, so his son became Emperor of all the lands of the Franks this was all of Austria, Belgium, Luxembourg, Netherlands, Slovenia, Switzerland & France (except Brittany), Spain north of the Ebro, Italy as far south as Rome (except Venice), Germany to the West of the Elbe, However Charlemagnes Son had 3 sons when he died and the lands were split between them.