|As Chrom is a Falchion wielder, he can serve as both an effective healer and a fighter, or he could opt to improve his combat performance further.
Weapon: Falchion is Chrom's weapon of choice. When given its special skill, it will grant Chrom +4 to all stats if he has an ally next to her. This increases his bulk when defending against attacks, while improving his already great Atk stat. The Falchion will also restore 10 HP every other turn, improving his sustain, which is especially helpful in endurance styled modes. Finally, it's effective against dragons, which means Chrom can help strike down any opposing dragons the player faces.
Assist: Reciprocal Aid is what allows Chrom to act as a healer of sorts, and is best used if he has Renewal 3 as well. With these skills, Chrom will heal 20 HP every other turn, as well as 20 HP at the start of each map for endurance styled modes. He can then proceed to share his pool of HP with injured allies and have his skills heal back up the damages for himself. Should the player use Chrom in other modes or feel like this is not necessary, then another Assist like Reposition can be used instead for its movement utility, helping Chrom move his allies around instead.
Special: Glimmer is Chrom's Special of choice, as it has a fast charge and helps him do even more damage. Given that Chrom won't always be able to double his foes, he'll want something that can charge pretty quickly and help him pack even more of a punch.
A Passive: Death Blow 3 is chosen as Chrom's A skill. While Chrom might not have the Spd to always double his opponents, he'll at least be able to hit hard on his first strike, so Death Blow will help greatly with this.
B Passive: Renewal 3 is an option for Chrom's B skill if he wants to serve as a medic for his allies, and should only be chosen if his Assist is Reciprocal Aid. With it, he can heal even more HP, and it lines up with his Falchion's self recovery, letting Chrom heal 20 HP every other turn, which he can then use to help heal his allies. However, should the player feel like this is not necessary, or use Chrom in less drawn out game modes, then Swordbreaker 3 is a great option for him as his B skill. This instead lets him duel with opposing sword users and come out on top.
C Passive: Spur Def 3 is an option for Chrom's C skill, as he comes with it naturally and it can bolster the Def of his allies. However, Chrom's C skill is flexible, open to be whatever the player needs. A buffing skill like a Drive or a Tactic skill could work well to help him support his team, but this is up to the player's team composition and discretion.
Sacred Seal: Heavy Blade 3 is an option for Chrom's Seal slot, as he should have pretty high Atk to take advantage of, especially with his weapon's effect. This will help him charge Glimmer much faster for his next engagement. However, this skill slot flexible, open to be whatever the player needs, depending on the player's team composition and discretion.