Your First 5 Star Unit.

Mine was a +HP -Res M!Robin during the first week or so of the game.

Which was awesome because that was my most wanted character, and pretty much hooked me on the rest of the game.

Mine was Merric, yep, Merric. The worst thing is was I thought he was a top tier unit with 40 Atk...

A +hp -spd Marth on day 1. I was extremely happy with him even after discovering that he practically had a completely trash IVs.

Y!Tiki pulled from one of the first days.
The funny thing is, when I was doing arena for the first months (wasn't really playing it knowing about merges and stuff) I didn't know hector was top tier, since I would just put Tiki there to tank.
Good times.

Mine was Sheena in the first 4 days of gaming when i didnt care for IV's lol

+Spd, -Hp Lyn on the Deep Devotion banner waaaay at the beginning of the game's release. Perfect IVs, too (aside from possibly +Atk). She carried me hard my first few months and she's still a favorite of mine even now.

Julia, for some reason I didn't use her a whole lot, and still don't (she has a terrible build - I gave her Desperation!)... I don't even think I checked her IVs ever (+Atk -Def).

Mine was a completely neutral IV Linde back when the game started. I also got a -atk +res regular Lyn in the same circle.

+Spd -Def Spring Kagero. Optimal IVs on an overall pretty good unit, but I didn't use her because she couldn't kill some enemies in the Training Tower, I was stupid.

Clair. +Spd -Res.

Clair. My first highly used 5* was a neutral Ike.

My first one was Linde (+Spe/-Def). A very good one and I didn't realize immediately when I got it.

Mine was an Eirika when she was first introduced.

Seliph. IVs unknown. This was back when he was 4-5* rarity. And back when SP was a lot harder to come by, I merged him into a +HP -Def duplicate so he could level up from 1 to 40 again for another 594 SP.

He's not a great unit but it's ok. If I want to change the IVs now, it's not that hard to do.

Mine was a -Spd +Def Delthea, although I have a perfect IV one (+Spd -Def) +1 merged today, I still kept her and I don't want to merge or fodder her. It was also the second stone I ever chose.

(After that, I think in the same summoning session, I got a -HP +Atk Karel, which is still the only one I have.)

My first 5-Star was a Nowi that was +Def / -Res that I pulled way back when the game first came out. (I think this was a few days after launch.)

She wasn't a focus unit--I'm pretty sure--but I was really happy that I got her just because she was a 5-Star and I knew who Nowi was from Awakening. She was used very often back then, long before Dragons got their adaptive damage, and is still a part of my Arena team today (though, the original was merged onto one whose IVs are now +Res / -HP).

Athena. I got her at 5 star when I first started playing almost two years ago, and I used her so much. I’ve now recently started to build her, and I’ve turned her into a force to be reckoned with. I honestly don’t know her iv’s, as I’ve merged her a few times, but she’s still a great unit. I kept the original, and I wouldn’t give her up for anything.

A +atk M!Robin on like day one. He served me well for a long time, hopefully he can get a pref weapon someday since he hasn't aged the best.

Mine was Julia in the banner when she was released, back in the day when i summoned her i've seen her as very bad unit, since Hector and Takumi were the most common threats at the time and she kept dieing to them, i don't remember the IVs. Now she is +5 and has +atk -hp IV

Prob BLyn from free summon CYL1.

First 5* pull was Lyn, and another Lyn (I feathered both of them :') without merging )

First 5* unlocking potential is Lon'qu and I loved him. He's chilling in my barracks atm

Sat there on release day and rerolled until I got +ATK/-HP Lucina.

Only took 6 hours.

+atk -hp Takumi. One of the best units in the game at the time.

A -res, +def Cordelia. Back on the Wyverns/Pegasus banners, friend thought it was a good idea, I end up with their waifu, and I never heard the end of it, rip

First unit I ever pulled was a 5* Kagero, +atk - res. This was back before Skill Inheritance, when she was a counter to the popular Takumi. She's now +7 and my Summoner Support (although I did switch IVs to -def).

-Spd +Res Peri, back on the Deep Devotion banner.
I still have her with 2 merges, hoping i find an optimal IV one.

Mine was Roy, and he also was my first summoned heroe. But he had really bad ivs (res+ atk-).

My first 5* units were Raven and Fae (same circle). Raven did a bit of work for me in the beginning since I didn’t have many 5* units, but eventually I discovered he was -atk, went “oh, THAT’S why he can never kill things,” and stopped using him. Eventually after SI came out I foddered his Brave Axe to Cherche. Fae, on the other hand, was +def -hp. She was my first and still is my best dragon. I ended up becoming a huge proponent of +def Faes long before the weapon refinery came out and everyone else realized how good a boon it was. *puts on hipster glasses*

Mine was a +spd -def Minerva. She used to be my only 5* green unit for or a while, and I even continued to use her after I got more green units that were better. She kinda just sits in my barracks doing nothing nowadays

My first 5 star was a Roy on Day 1
I don’t even use him anymore, just have him there on a podium as my first five star. I thought Roy was Top Tier and one of the best units. Look at me now, missing practically every five star in the game

My first Five Star was Alm which is also the first one I did a merge with too which at the time I didn't the significance of it. I'm also glad that Alm eventually got an upgrade cause he was my main Sword unit till I finally realize how broken Ayra was.

Claire.

Mine was peri

A -Atk Ephraim was my first 5*. I used him for just about everything. I didn’t even know IV’s were a thing up until Michalis showed up as a GHB. Even after learning he was -Atk I kept using him. Recently I pulled a +Atk/-Hp Ephraim and merged the old into the new, but the old Ephraim still holds a place in my heart

Mine was Marth! I remember I was really happy.
Back then I didn’t know about ivs and I kept him as my main, and with a terrible build too, since I went a bit crazy when they implemented inherit skill. I kinda want to do him justice and give him a decent one.
I’m also glad he now has a legendary alt.

Summer Elise, she was my favorite unit for a long time. I remember being both thrown off when I first heard her "OOOH HOT" and "YAAAAY" voice lines.. Even with her crappy IVs (+Res -Spd) I used her all the time. Of course I have other green mages that I use more now but I still like using her from time to time as a Reinhardt check for AA.

My first 2 5 stars playing the game were Roy from RnG and Brave Roy from free summon :)

+Spd -Res Y!Tiki, first-ever pull. Used her a ton in the beginning, then she sat in my barracks for a while, then when dragons got upgraded and I got a Ninian (aka Fortify Dragons), she became one of my most used characters again!

Mine was + defense res the best its cool same pool I got Marth + spd -hp on launch day so I was pretty happy first unlock potential cherche +Ark - res great ivs didn't know her ivs for awhile tho. I have an. Other account where it was funny enough Mia+ spd -res and same pool Delthea + spd -def on Farfetched heroes