Soren is my absolute favorite Fire Emblem unit, and was my first completed 10 unit. To be honest, I finished him a few months ago but only recently decided to showcase him here. I wanted to make my Soren stand out from what I've seen elsewhere--he has a decent offensive statline but he's also deceptively bulky, and the build I put together for him tries to take advantage of that.

IVs: Spd -HP, because his weapon refine brings his HP back up, and I didn't want to lower either his defensive or offensive stats. With Spd, he avoids a good number of doubles, and can double most opponents he fights, particularly when supported by his teammates (Eirika and F!Corrin).

Weapon: Eff-Refined Wind's Brand--to be honest, I don't usually use the Owl tomes. However, I've found that I really like them with this build. He can pick up surprising offensive abilities with the Owl tome effect active; during the Legendary Grima battle, he won the battle for me after I realized he could pick up sufficient speed if positioned correctly. With the Chill Attack refinement, his survivability is greatly increased against high-Atk physical units with DC who might otherwise kill him.

Assist: Rally Spd/Res--this is basically for Arena points, but his teammates appreciate the buff to both stats.

Special: Iceberg--Even though Aether is worth the most points in Arena, I find that it lowers his combat viability. As my Arena core is three infanty pre-CYL Heroes, I'm not staying in Tier 20 anyway, so I prefer the increased usefulness in combat. At some point, I may end up caving and giving him Aether.

Slot A: Distant Defense--This is really the main part of build, which gives him mixed-phase usefulness. I stack his A-skill with the Distant Defense Sacred Seal to give him a surprisingly bulky Enemy Phase at range. Combined, they bring his Res to 45 and his Def to 33, which allows him to survive most things when combined with his solid Spd. Of course, he still takes some damage, particularly from Archers. With the double-DD combination, I frequently use him to bait out even some red mages, as they won't kill him.

Slot B: Desperation--After tanking one or more ranged hits in one or two Enemy phases, he is usually knocked into Desperation range. This makes him more viable for use in Player Phase, as he can get two hits out of the way and usually kill his opponent.

Slot C: Drive Speed, as a support for his teammates. I honestly love the Drive skills, and use them frequently in my builds. Plus, I keep pulling Tailtius.

Sacred Seal: Distant Defense, for reasons described above.

Support: Legendary Ike, who was part of my Arena core before I decided I really was too broke to realistically 10 him. However, I still use L!Ike in my starting Arena Assault lineup, so the support stays. Besides, I refuse to ruin their beautiful relationship.

In case anyone is curious, he is currently equipped with the Snorkel, because I am desperate for Summer Soren. Please IS, I'm begging you here.

So there's my Soren build! He was definitely worth the investment--a very good pick for my first 10 unit.