Genuinely this question has plagued me for so long. Like there’s no way a trained pegasus knight would be less durable than a little kid. However, I could see the pegasus itself being that frail.
So FEU community, I bring this question to all of you.
This is giving me a sick idea, but what if when a mounted unit dies, you still keep them, but in a dismounted form, also cutscene where they grieve for chonky the horse or whatever
You read my mind lol, that’s something I thought about while making this
Alternatively, make it so another unit has a secret promotion into a mounted class, but only if a specific mounted unit dies. They inherit the mount.
Well, obviously the unit needs to die when the unit dies, otherwise they would just end up captured or return to camp and get a new horse and thus the whole “the unit died“ thing would kinda get undone.
Whether the horse dies, though, it depends. If we look at real life, certain anti-cavalry weapons were intended to target the horse - pike lines were effective because a horse would just impale itself on the pikes. So if you’re killing a mounted unit with a halberd or horseslayer, you probably are killing the horse indeed. With bows or short ranged weapons you’d have more luck taking down the rider instead.
Plus in medieval battles they often didn’t aim at the horse because horses were valuable, expensive, and could be reused if they survived a battle but their rider did not. A horse without a rider is just an animal which will probably just flee the battle immediately and can be captured after the battle, killing it is wasting precious mounts or money.
So jury’s out on killing the mount if you aren’t using a pike. Pegasi, though, they probably almost always die when you kill a pegasus rider unit. They’re fast and flying, so if you’re aiming at them with a bow you’re likely aiming for the wings and downing them to the ground, where they almost certainly break their necks or bodies while crashing. And if you’re engaging a pegasus rider in melee, the wings make it difficult to target the rider since they cover them up from the sides, so you may as well not bother and pierce/slice through the wing, sending the pegasus to the ground in the process.
Only the unit because I don’t want to think about all the horses dying 
I headcanon the horse running away out of fear
BLOOD FOR THE BLOOD GOD!
Flier’s arrow weakness doesn’t make sense if the mount doesn’t die so IMO, both die. The mount dies first and the rider dies to fall damage 
So one cool mechanic about Berwick Saga is…
FE definitely plays it both ways, Eda and Gerome’s death quotes are them releasing their mounts.
There are counter examples, such as Gerome’s quotes in the future past DLC.
I think Cherche/Zelcher from Fe Awakening answer that with Minerva, the unit die and the mount survive
But why is that? What is the reason for one to live and the other to die?
like for instance if a mounted unit is a man carrying on his back a horse, which one would die if the unit is defeated?
Historically, weren’t massive swords and spears and swords with spear-like long hilts used to express something to the tune of “**** you and the horse you’re riding”? Fire Emblem regularly has characters perform feats of superhuman strength/agility/whatever, just look at the weight and thickness armour has to have before it does anything. They could totally throw a knife so hard it hits a Dragon Rider and shatters all their bones and the Dragon’s bones too.
At least the unit, possibly the mount as well depending on how they were killed. That’s what I’d assume, anyway.
idk the rider dies and the horse/pegasus/wyvern flees out of the wild
I think there’s an opportunity to have a mechanic where you can fuse both a mount and an unmounted to become a certain class line (while also retaining weapon ranks). Or you can simply have mounts be an alternative to seals; where you must gain a certain support rank with mounts in order to achieve said class lines
Plus in medieval battles they often didn’t aim at the horse because horses were valuable, expensive, and could be reused if they survived a battle but their rider did not. A horse without a rider is just an animal which will probably just flee the battle immediately and can be captured after the battle, killing it is wasting precious mounts or money.
There’s a flipside to this. A lot of medieval warriors that could afford to fight mounted were typically more wealthy than those who could not, and usually either of a noble or urban upper class background. It was often attempted to capture these individuals so that you could sell them back to their families for ransom, and sometimes those sums could be enourmous, a lot more than what their horses were worth.
An extreme example would be that when the French King John II was captured by the English at Poitiers (granted, he marched into battle on foot, so in this specific case there was no horse to kill), the ransom literally bankrupted the French royal treasury, causing severe political turmoil. And funnily enough John would end up voluntarily returning to captivity in London after his brother Louis escaped on his own, showing just how seriously these sort of things were taken back then.
Does this really need to be in Offtopic? It seems pertient enough to Fire Emblem to me.
I mean they both dissapear when they are defeated right?