Story:
Frederick can always be found with Chrom throughout his journey in Ylisse to stop the Ylisse-Plegia war. When Emmeryn is nearly assassinated, he advises her to leave the capital for a short while. Emmeryn later ordered Frederick to stay with Chrom, which he accepts humbly. After Emmeryn's sacrifice, Frederick feels that he's failed his duty as a Knight of Ylisse, but he recovers and vows to continue to serve and protect Chrom and Lissa.
After the war Frederick becomes the newest knight captain for Ylisse and devotes his time to keep the peace in Ylisse and train new recruits.
Personality:
Frederick is extremely serious and has a no nonsense personality. He is a skeptic and earned him the nickname "Frederick the Wary" from Chrom. He is very patient, dealing with Lissa's antics and Chrom's reckless behavior to no end, but Frederick cares for Chrom, Lissa, and Emmeryn, feeling the need to protect and serve them at all costs. He also loves building fires.