AB p.15 & p.17, p.57, BRB p.180: Marius Leitdorf has been killed. P.17 tells that it happened in 2520.
BRB p.177: we are in 2522.
AB p.13: Averland throne is confirmed to be vacant since the death of Marius Leitdorf.
Averland, one of the Empire's richest part, and a vital bulwark against the Orcs' invasions, has been left without Count for two years now.
Note: previous army book versions and first supplementary rule to play Marius Leitdorf were no different.
Nothing saying your army has to be current timeline either anyway.
Despite being already dead at the time, he used to have his own model in the previous edition, supported by supplementary rules.
Now, he is still dead, but there is a new model and his rules are part of the army book. His death is even recalled in his own fluff.