Lyn

This is a Røkkr Sieges build for Lyn. Guard Sword+ (+Atk) increases HP and Attack, and can block Umbra Blast/Eruption/Calamity. Astra is the go-to Special for Røkkr Sieges, and it’s power is boosted by “Death Blow 7.” Special Spiral makes it a 2-hit Special, and finally, Pulse Smoke is for more help with blocking the Røkkr’s Special.

Lyn is an interesting unit that, if allowed to set up, can be an incredibly effective sweeper with the ability to one-round even blue armours. She plays well with other units that have the ability to damage their allies, such as Fallen Berkut and Lif. Having a unit with such an effect allows Lyn to set up all her HP dependent skills without seeing combat first. This build aims to be as optimal as possible while also remaining relatively F2P friendly. As of writing, the only suggested skill not readily available to all players is Time's Pulse 3. The advent of Resplendent heroes obviously makes Lyn significantly better, but this analysis will be based solely on the regular version.

Preferred IV: +ATK/-HP or -RES

With a measly attack of 28, Lyn depends on an Attack Asset to ensure the highest number of 2 hit knockouts possible. While no other assets are nearly as beneficial to Lyn as one in Attack, a Defense Asset can also be quite decent, as it gives her a solid +4 as opposed to the usual +3. While this build plays to Lyn's strengths by mostly ignoring her speed, a Speed Bane does lower her ability to double 2-ranged units and units equipped with Fire-Sweep weapons, so it should be avoided if possible.

Weapon: Sol Katti (+Eff)

Sol Katti's refinement gives Lyn her only niche compared to more newly released sword units by combining Desperation and Brash Assault once she reaches 75 % HP or less. This combination allows Lyn to mostly ignore the Speed stat that so many other sword units must invest in to ensure their double attacks, as well as freeing up her B slot for Wrath.

Assist: Reposition / Draw Back / Ardent Sacrifice / Reciprocal Aid

Lyn's role on the battlefield is purely to slice up fools, so her assist skill does not particularly affect her performance and can be left to player choice. Reposition and Draw Back are both universally useful movement assists that have both offensive and defensive applications. Meanwhile, Ardent Sacrifice and Reciprocal Aid are utility assists that will allow Lyn to effectively damage herself - lessening the need of an ally such as Fallen Berkut or Lif on her team.

Special: Luna

No other special comes close to being as good for Lyn as Luna. Luna's 3 turn cooldown synergises perfectly with Wrath and Time's Pulse, allowing Lyn to always activate her special on her second attack of combat assuming the opponent has no skills that counter special activations such as Guard or Special Fighter. If such skills are present, stall for a turn to let Wrath put Lyn in special activation range. Ignoring 50 % of the opponent's Defense, along with the +10 damage from Wrath allows Lyn to defeat blue defensive walls such as Berkut Lance Effie without any buffs or supports from outside sources - though Lyn will certainly always appreciate any attack buffs she can get regardless.

Lyn does not have high enough base stats to make use of other specials such as Dragon Fang, Glacies or Iceberg, and using those will severely hamper her performance. Even with a build taking advantage of the significantly rarer Flashing Blade 4, Luna is still better than 4 turn specials like Dragon Fang or Glacies, as evident by the mass duel simulator.

Passive A: Brazen Atk/Def 3 or the inevitable Brazen Atk/Def 4

This is where Lyn finally goes against the grain of other sweeper sword units in the game. The niche that her unique refine gives her allows her to invest in defense rather than speed while still doubling, making her deceptively tanky! The A and Seal skills of this build combined gives an unmerged +Atk Lyn the defense stat of 40, while other sword units with similar roles, often considered better than Lyn in every way, struggle to reach 30 defense with optimal builds. 40 (or 44 with a Defense Asset) is an interesting threshold of bulk where just a few additional buffs from her team lets Lyn take very little damage when fighting axe or other sword users. This unexpected bulk allows Lyn to survive a surprising amount of attacks in spite of the damage she is required to take for it to activate. It should be noted that Lyn's defense is quite meager before getting into Brazen range. Look for alternate ways of damaging Lyn instead of throwing her into combat at 100 % HP to get the full benefit of her added bulk.

Other A slot skills that focus more on speed, such as Swift Sparrow, Brazen Atk/Spd or Life and Death offer Lyn very little, and using them will make Lyn merely an inferior version of most other sword units out there.

Passive B: Wrath

Wrath is undoubtedly Lyn's best B slot skill, and is readily available by eating Astram. Having the same requirements as her sword and brazens, Wrath is the perfect fit for what Lyn is trying to do. Lowering her Luna cooldown and adding more damage on top is just too good to pass up on.

Passive C: Time’s Pulse / Even or Odd Atk Wave / Atk Smoke

Time’s Pulse synergises well with Wrath, activating at the same time and putting Lyn's Luna cooldown down to 1 at the start of your turn if she is damaged. From an optimization standpoint, this is by far her best C skill and should be used if possible. That being said, Lyn also has a lot of other options for her C skill that, while worse, are certainly cheaper and remain effective.

Even or Odd Atk Wave are both good ways for Lyn to self efficiently buff her own attack stat without needing help from her allies. With the lack of Time's Pulse, try to time the buff from your Atk Wave with the second tick of Wrath required to go down to a 1 turn cooldown of Luna. This also gives Lyn some utility by buffing the allies around her, far from a bad choice!

Atk Smoke is another possible C skill that seeks to take advantage of Lyn's deceptively high bulk. After defeating an opponent on initiation, she can then give all other nearby enemies a hefty -7 debuff to their attack to ensure she survives the following enemy phase. At an effective 47 defense (51 with Defense Asset) before accounting for buffs from her teammates, Lyn should be able to handle most things the enemies can throw at her.

Sacred Seal: Brazen Atk/Def

As previously discussed in the A slot analysis, using Brazen Atk/Def as her sacred seal gives Lyn the unique niche of being able to 2 hit knockout most units in the game on initiation, while also giving her the bulk to withstand multiple attacks if it comes down to it. With most fast units in the game now being able reach 50 speed, there is simply no optimal way for Lyn to compete with them in the speed tiers with her poor attack stat and merely average speed. This build, focusing on increasing her attack and defensive bulk while depending on her weapon effect to double, is a cheap and effective way for Lyn to carve a niche for herself in the oversaturated pool of fast player phase focused sword units.

Preferred IV: +ATK,+Spd / -HP
Weapon: Sol Katti (+Spd, +Atk)
Assist: Swap / Reposition / Rally Atk Up +
Special: Galeforce
Passive A: Flashing Blade 4
Passive B: Null-Follow up 3
Passive C: Joint Hone Spd / Threaten Atk/Spd 3
Sacred Seal: Brazen Atk/Spd 3

Lyn is still in a weird place. Her sword's refine is good, not great as Brash Assault becomes more and more outdated with the slow powercreep of range units making it useless (it does not work on units that cannot counter you). So I have been waiting for a weapon and skills to come along to make use of the #1 waifu in Fire Emblem in some way. Sure, I could make her use my Mia-Armorsmasher build to become an anti-armor dragon slayer, but I wanted something a bit more unique and universal. I first thought I found it with Cake Cutter, but through various testing, I figured out that I was just refining Lyn the wrong way.

Preferred IV: +Atk/+Spd/+Res are all winners for a boon. With Atk, you get a Lyn that might not do 0 damage as much. With Spd, you help activate Flashing Blade. And with Res, you get yourself access to some Ploy skills and protection against dragons. Choice is ultimately yours, but I like to go with power first.

Weapon: Sol Katti (+Spd) gives Lyn some much needed speed in a world where everyone seems to raise the bar farther from her. You can easily flip this to +Atk refine if you have a +Spd Lyn, but this is where the juggling comes in. +Atk only gives you +2 attack while the boon gives you +3. You want Lyn to have a good mix of both attack and speed and diving heavily into one, leaves the other worst off. Lyn's attack is bad, but a boon makes it workable. Her speed is good, but has a lot of competition from newer units. My preference is the healthy mix of a +3 Atk boon and a +3 Spd refine. Your own results may vary, but this is what has worked for me. Keeping the Desperation effect but dropping the Brash Assault is incredibly important because that +3 Spd is going to help close that gap for Lyn where Brash Assault isn't as useful (assuming you use dragon flowers and a summoner support and/or unit support). While a weapon like Cake Cutter is still going to give you more oomph on initiation, Desperation will literally mean Lyn kills or is killed because she can attack twice before the enemy. This is the beginning of how Lyn can start to mimic Mareeta with some finagling.

Assist: Swap is what I prefer for infantry units, but others swear by Reposition. Or you can grab a Rally skill if you are hunting for Arena score.

Special: Galeforce works great for this build and is the cheaper option since Lyn already comes with it. Moonbow or Luna is good for getting in some extra damage (and seeing Lyn shout things) what with Lyn's attack being mediocre and all. But with Galeforce you get to preform some crazy shenanigans and help get Lyn into Desperation/Brazen range as it is nearly impossible to avoid damage on a Galeforce user.

A slot: Flashing Blade 4 is what helps pull this build together. It is great for lowering Lyn's CD for Galeforce and for giving her some much needed guaranteed damage.

B slot: If you are going to fodder off a Mareeta for Flashing Blade 4, you might as well grab Null Follow-up while you are there (Flashing Blade 1-3 being available on a grail unit). Chill Spd 3 is great as a budget option, but as we move on, that will not be needed as Lyn should become fast enough to double most people with the proper investment. Null Follow-up is great if you want to guarantee that Lyn attacks twice for maximum CD and damage on units like Myrrh and Surtr.

C slot: Almost anything can go here. Joint Hone Spd or Threaten Atk/Spd is good to keep Lyn's speed up higher. But any Wave skill will work or any support skill that you might want for team support. I lean toward any skill that improves Lyn's own stats, though, as I do not want to take any chances that she becomes outmatched.

Seal: This is where Lyn separates herself from Mareeta. Mareeta's weapon requires her to be above a certain HP threshold while Lyn's weapon is the opposite. Because of this, Lyn can take advantage of Brazen skills more reliably and allows her to catch up to faster folks like Mia and Mareeta. This is crucial for securing doubles and kills on both them and tanky units like Surtr.

The thing with this build is that of all the skills here, the Desperation effect of Lyn's weapon is the only one that cares if you initiate or the enemy does. This is a very dual phase friendly build that allows Lyn maximum versatility in the field and encourages the unit to do what it does best. If you are a fan of Lyn and want to see her be relevant again, despite what rankings have her as, this is the build that will allow her that chance.

Fury-based set to take advantage of Sol Katti. Seal and C-skill are to help Lyn's defense, because her Resistance is fine for what this build tries to be.

*Update* The build is still to get her HP at around 50% still however she has much better skills that have been introduced. And she is a +2 merged unit so her stats have increased slightly.

So brash assault is now brash assault 4 and built into her weapon, and with the addition of brazen atk/spd grants her +7 for each stat when her HP is 80% or less of her max. Wrath adds extra damage to luna however moonbow could work too. And atk smoke helps her bulk as well as her teammates bulk as well. As for a seal quicken pulse could work with luna but 3 extra attack seemed more helpful, speed could work too. I'd say this is a better build albeit more expensive. but both work amazing.

Basically this build is to get her under or at least 50% of her max HP.
She is best at initiating attacks with the help of death blow and brash assault and with desperation 2 built into her weapon most units will fall to lyn if she attacks first.
Reciprocal Aid helps with getting her to that threshold quicker and easier and luna is for those units with higher defense stats to ensure victory.
Threaten Def is used to give her a bit more attack power and since she usually hits twice it grants her +10 more damage most of the time.
My lyn is +HP -DEF so if you have one that is +SPD or +ATK she could be even better.