But what if it was a spear fighter like Sharena?

Fire Emblem has more weapons that just swords….
Granted, Smash does a TERRIBLE job showing that:

7 playable characters, all use swords as either their main or secondary weapon.
The FE related item, the Killing Edge, is a sword.
2 out of 3 assist trophies are sword users, Tiki being the exception.
The FREAKING LOGO is a Sword (Falchion I guess)
The spirits are the main exception, having Staff users (Wrys, Elise), Lances (Hinoka, Ephraim), and Tomes (Nino, Young Celica [along Young Alm]), and maybe more. But alas, they're glorified stickers, so…