I am currently writing a novel with a medieval Western European setting. One of the protagonists was a general some years ago, but he retired from a life of war after moving to another nation and starting a family. He has since become a castellan for the ruler of the nation, but this role is more of an honorary position and a gift of sorts from the ruler, both as a sign of friendship and as a recognition of his past achievements.
To offer some background, the general was the son of another general. The general's father left his homeland and his impoverished family at the age of 18 to find employment for himself and a brighter future for his parents, sister, and nephew. He had no education nor any particular skills, and so he enlisted in the army.
Here, he prospered. Despite his lack of experience, he quickly became the most accomplished soldier the army had ever seen. He was not the best with the blade, nor had he the strongest arm, but from the day he first set foot on the battlefield, his will was stronger than the armour any steel could forge, and his courage and determination as stalwart as the eternal mountains of his new home. Soon his skills and his brawn developed to rival even the hardiest veterans of both his allies and his opponents, but it was his undying morale and unending physical and mental endurance that carved his name a place in history.
The years waned, and no man could hope to kill him, no army could hope to defeat him. And none did. His life was lost to sickness mere days after his 40th birthday. However, there was someone to replace him: his son. The old general had trained his son brutally since the day the kid was able to lift a sword. The general's son was also naturally gifted with the talent and strength his father worked hard to earn. The father's expectations for his son were impossibly high, pushing the kid farther than what even the old general himself was capable of at the same age. Yet the general's son did not disappoint. When the old general died, his son was only a couple of years older than what the general had been when he left his homeland. Yet the young man surpassed even the legend his father had created.
However, after only a couple of years serving in his father's position, the royal family died in a coup. The war was lost. The new general moved to a politically neutral nation to escape the possibility of persecution and started a new life, devoid of taking lives and watching friends die. He married and had kids, and though he kept in shape, he had no need of maintaining his strength and skills; in fact, his new role of castellan was a rather placid one.
The book opens with his family's death and a return to a life of killing and war. My question is this: What effect would a 15-year absence from war and sword fighting have on the skills of a man who was once the best swordsman in the realm, and to some extent, the best in recent history?