Military action
De Ro while technically being emperor was still the best field general and thus stayed in the field against the gnolls. During the campaign there would be numerous attempts to kill the Emperor and some would get quite close, yet he would survive and win the war.
The war with the gnolls was much different then the first battles against them ten years ago. As compared to now those were simply probing attack meant to test the defenses of the then kingdom. This felt like the gnolls were committing a war. They had rough supply lines, mages in the field to heal their troops, mages in the line to fight, as well as troops that were much more relevant to orderly combat. The gnoll army he faced now would take a real army to fight, not just the small fighting force he had pulled together. He sent back for aid, troops, and supplies, he received everything he needed quickly. He received a regiment of elven battle mages, In addition to this they received five regiments of cavalry and 20 regiments of infantry. With this first initial supply of troops and supplies De Ro focused on removing the tendrils of gnolls breaking off from the main army and crushing them. Once the secondary and tertiary tendrils were cut off he turned to the main army and bore down on it. Using he Calvary he was able to encircle the gnolls long enough for the battle mages to remove them from the world. The total campaign took about 2 years to remove the gnolls, most of it spent chasing and removing smaller splinter cell groups living in the area. The wall was rebuilt and reinforced, also armed with a variety of new weapons most of which were variations of the crossbow but larger and more deadly.