Not as popular as his son, but Eliwood is a good lad. For appearance:
TW: Eliwood
Supporting tags: 1boy, short hair, red hair, blue eyes
Outfit: Eliwear, circlet, blue shoulder armor, two-sided cape, red cape, blue cape
Other: holding weapon, sword, holding sword
Illustrious Notes: The lora is pretty heavily tied to his clothing and takes a little work to get him wearing something else. Durandal can be generated (usually poorly) with "Durandal (fire emblem), huge sword". The rapier is "rapier", sometimes it generates more than one.
It should take care of the rest of the outfit but you could add things like "pants, boots" and other clothing bits if there's trouble. Sometimes his hands turn out weirdly large so "large hands" can be added to negatives. This was made primarily from art of his appearance in Blazing Blade, not his other appearances in Fire Emblem Heroes. His Resplendent and Brave outfits were in the data mostly to teach the model that he can wear other clothing. In the Pony version I forgot to differentiate between his rapier and the Blazing Blade itself when tagging with "sword" so if you put that in it might look like a weird mish-mash. Sorry