Elves were excellent archers; however, apart from a few exceptions who were fervent in actual combat, most lacked sufficient close-combat capabilities. When the commander on the ground realized that the artillery could not provide support and his troops were being defeated by Charlemagne's savages, he decisively ordered a retreat. After the Chimera units took over, the situation on the battleground drastically changed once more.
Within the Wehrmacht hierarchy, Chimeras were considered as consumables, just like bullets and shells. The Elven gunners felt no qualms about firing at these consumables, even when they were mixed with the enemy troops.
With the psychological burden lifted from the Elven gunners, the people of Charlemagne made it immediately clear that Alexander, just the barrage of shells was deadly enough, not to mention the cannon fodder.