|This build has the sole purpose of taking advantage of the new Guard Bow+. With her new Bow, she can have high defensive stats when attacked during the enemy phase. With Guard Bow+ and Distant Def, in the A slot and as a seal, Setsuna can reach 40 defense and 41 resistance when attacked by a foe using bow, dagger, magic, or staff. This makes Setsuna a powerful enemy phase tank, especially with possible buffs from teammates.
An issue with this build is Setsuna's naturally low attack, even with +Atk/-Hp ivs. Yet, with her high defensive stats she can deal massive damage with Iceberg as her special. If you have access to a unit with Infantry Pulse, then Glacies would be a better choice to increase her damage output.
Any assist skill can work, with Reposition and Swap being most useful for movement.
This build is centered around her A Skill being Distant Def. While this is a rare skill, I feel it is the best one for her with this weapon.
For a B Skill, there are a few options. Bowbreaker is an option that allows for less SP grinding, but other breaker skills could be useful as well. However with the restrictions of this build, breaker skills used should only be those that counter ranged foes. Another option for a B Skill is Cancel Affinity. This skill makes Setsuna a very powerful counter to raventome mages, especially with her high resistance.
Any C Skill that assists those on Setsuna's team can work. Hone skills are most likely the optimal choice for this build seeing as it is heavily reliant on the combat occurring during the enemy phase, so skills like Threaten Def won't have much of an affect.
This build fills a very niche role: allowing Setsuna to become a ranged tank, while sacrificing the damage output of Quadsuna builds and forcing all of her battles to occur during the enemy phase. With the new weapon refinery feature Guard Bow+ can gain more attack, speed, or resistance, which are the upgrades I would recommend.
The Guard Bow+ with this build allows Setsuna to lure her foes into a trap, instead of falling into one herself.