Rhiannon

Based on Fire Emblem Heroes. Rhiannon is a Summoner brought to Askr from 2020s Earth and given the Legendary Relic known as Breidablik. While initially very confused, they became very fast friends with Princess Sharena and learned to wield the pistol-like Relic on their own, summoning other Heroes into combat. They work hard to try and befriend everyone who arrives, understanding the confusion of being yoinked from another dimension... apparently. They guess? Who even knows how this works? In the Heroes' "5 Man Band", they are typically the Smart Guy and share the Lancer role with Prince Alfonse.

Rhiannon is nonbinary and uses they/them pronouns. They're slightly taller than Prince Alfonse (who is 5'11"/180cm apparently). Other than the pistol Breidablik, they wield a bastard sword - but instead of holding it in their hands, they levitate it in front of them and use magic to swing it around and take out enemies. Their special combat move is called Sol, which heals some of Rhiannon's injuries when it activates. Rhiannon is decent with a sword, though doesn't really use it much if they can help it. They mainly picked it up as a back-up plan; Breidablik is a distance weapon, and thus not incredibly helpful if someone gets in close enough to stab them. Thus they started training as an alternate way to defend themself. They have a skinnier build, lean but more toned than you think they would be -  though they can really only take out Magic users consistently and have trouble with other melee fighters. Rhiannon has no talent for magic, other than what's required to power their Gun Relic.

Rhiannon is more often than not seen wearing a tambourine on their head. No explanation is given for this. Everyone just kind of... accepts this about them. They're not particularly outgoing, but enjoy conversations with Heroes and can often while away hours at a time talking about interesting things. Half the time they're nose-deep in some book taken from Askr's castle library; they will read literally everything they can get their hands on. This is one thing they have in common with Prince Alfonse; they're both voracious bookworms. They enjoy the various holiday events and challenges that come around, and while Prince Alfonse sometimes gets on their case for getting too involved, Princess Sharena goes all-in and joins Rhiannon in games and costumes. Dress up is fun! They're fine wearing clothing trending towards masculine or feminine, they don't really have a preference.

While they do try hard to treat their allies well, Rhiannon is kind of awkward and closed off and only really seems collected in combat. They've earned their spot as Tactician, dammit. They listen more than they talk in conversation, and they're not always the best at reading the room. But they do, in fact, try, and they earn respect and affection from others anyway. Somehow. They're a little confused by this, honestly... So far, Rhiannon has shown no signs of sexual interest towards any Heroes or allies, and anything that could be interpreted as flirting or courting is just as easily justified as an awkward bean trying to be a good friend. This doesn't stop others (usually Sharena) shipping them with someone and wondering who they'd be interested in.

The units that join their army by default with the start of each new story are Fjorm, Eir, Peony, Reginn, Ash, Seiðr, and Ratatoskr. It's fine to draw them with any of these girls in a friend capacity. A more detailed list of my personal favorite FEH units are under the spoiler tag below (it's kind of a long list)