|As the Ultimate Strategist, Soren here's job is to provide a variety of buffs to guarantee any battles are won well before they start. He does so by providing a variety of buffs to your own team while weakening one of the opponent's hardest hitters. This build has two subcategories you could go into to fill slightly different niches, in addition to his primary. First, we'll discuss his main role as a support unit.
Wind's Brand. Using the Wind's Brand Soren gains the ability to reduce the attack of the strongest enemy by 7, a pretty hard nerf to the opponent's strongest hitter. This can result in them doing a total of 13 less damage PER ATTACK to each of Soren's allies, potentially more depending on weapon triangle advantage, and can make him an extreme annoyance to find in the arena.
Res/Def Tactic 3: Although it means he can't work on an infantry-based team, these skills combined allow him to provide +6 to the defensive stats of all nearby allies throughout your opponent's turn, which will result in them taking significantly less damage and, combined with Wind's Brand hitting their strongest unit, make his allies misery to try going through.
Draw Back: A way to get one of his allies out of trouble without risking himself, as Soren needs to be in a position to support, the fact Soren himself moves back as well is of utmost importance
Iceberg/Aether: Aether is primarily for scoring purposes, as Soren himself isn't supposed to fight enough to trigger it, while Iceberg takes advantage of his fairly high res to help him finish off opponents. However, if you decide to go into the Warding Breath build, Aether is somewhat useful for taking out his magic-using rivals.
However, both of these sub-builds have the huge disadvantage of being extremely fragile physically, even to opposing blues, and as such he must be protected at all times
Build A: Fury, Desperation, and Wind's Brand (spd)
This sub-build allows him to have a secondary focus on his nuking abilities, with Fury and his Wind's Brand bumping his speed all the way up to 41, potentially 43 with support bonuses. This is enough to double most units and increases his attack to a more respectable level with Desperation allowing him to take out his targets without having to fear counterattack once he's low enough.
Fury: A solid +3 boost to all stats both improves his offensive power and makes him less likely to get one-shotted in his first combat, after which desperation is likely to be active and eliminate all your counter-attacking worries
Desperation: Since Soren is rather frail, we want to activate this ability as soon as possible, thus he will be able to take advantage of his massive speed to double most of his targets before they get to fight back, especially important if the target in question is a Black Knight or other low-resistance reds.
Build B: Warding Breath, Chill Spd 3, and Wind's Brand (res)
While Build A's secondary function was that of an offensive nuke, Build B is a more effective support unit that also serves as a mage tank, giving him a bit more flexibility overall. The Wind's Brand is given the resistance bonus both to increase the damage Iceberg inflicts, and make him better at taking magic damage. Just don't let anyone with a sword near him and he'll be fine.
Warding Breath: Increases Soren's Resistance while building up Iceberg. There's a good chance that whoever you use Soren to lure will be fast enough for no one to get doubled, however this will simply allow Soren to initiate and finish it off with his Iceberg, as his attack is still somewhat respectable. It also makes it more possible for Aether to go off, useful primarily for Tempest Trials but one that boosts his overall proficiency as well.
Chill Spd 3: The main reason to go into this version, Chill Spd allows you to reduce another stat most sweepers tend to have plenty of, speed. Doing so can often completely cripple your opponent's best attacker making it even more challenging to break through Soren's companions. In addition, sometimes you'll get lucky and have opposing units tie for the highest speed, in which case they both get the debuff. Isn't that handy?Uni
Suggested ally abilities:
Attack Tactic 3: Since you'll have to mix unit types to use this, Attack Tactic is always a solid skill that will help Soren burst through his opponent's.
Anti-dragon units: Units with weapons like the Falchion can often negate Mage-Tank Soren's biggest weakness, a complete inability to do his job against dragon units. Though they hit resistance for the most part, on a fragile ranged unit like him these dragons can take advantage of his much lower defense.
Reposition: It is vital that this Soren build remain near the back lines on most occasions so as to keep his buffs coming. As such, Reposition sees a bit more importance than usual