|Lissa has some of the best mixed defenses in the game, and unlike her counterpart Sheena, her boosted BST gives her an actual speed stat and repsectable instead of mediocre Attack. Unfortunately, her speed only reaches 30, easily doubles by many of the fast Swordfighters and even mages in the meta. As a result, Lissa pts to ignore her speed altogether, and instead make use of her massive Res and Def stats to survive most long-range assaults in the game.
+Atk IVs are best, allowing Lissa to deal 6 extra damage per round of combat. +Res or +Def is still a beneficial upgrade. -Spd is the best bane as her Speed is not enough to do her much good except against other slow targets whom she could double (Cases that Vengeful Fighter 3 will hanfdle.)
Weapon Choice: Slaying Axe+ is a slight yet significant improvement over Handbell+,reducing the Cooldown of Ignis to allow the execution of Ignis in 1 round of combat. Handbell+, however, provides bonus stats when being attacked, which is almost always happening with this build, affording her extra staying power, however little it is.
Refine and Seal: In both weapons, the same refines apply. A +Def refine allows Lissa to become nearly immune to archers and increases her chance of surviving special procs from Ayra and Mia. However, +Res allows her to potentially survive Red Mages when combined with Distant Def 3. If you have a defensive boon, the refine should amplify that boon, and the build should be taken in the direction of that boon, replacing Ignis with Glacies if needed.
The Seals also depend on the above. Ifyou have a +Atk or +Def boon, grab a +Def refine and use Close Def to survive Ayra in Ward Armor teams. Distant Def is picked if you either don't care about guaranteed survival vs. those two (i.e in non-Arena modes), or if you have +Res refine and a Res boon.
Assist: Pivot allows Lissa to move with her infantry allies down hallways and chokepoints without being left behind. It also allows her to mvoe with armored allies at normal speed without Armor March. Swpa cna either be a budget option, or for an Armor Emblem team with 2 Armor Marches and only 2 Wards.
Special + B Skill: The special choice of Aether vs.Ignis/Glacies is dependant solely on the weapon used. Aether works better with Slaying Axe +, allowing Lissa to execute a unit with it on her second attack: Unit attacks -> 3 charge, Lissa attacks -> 1 charge, enemy doubles if > 31 speed -> charged, Lissa unleashes Aether -> 4 charge and a likely repeat for another fight. With Handbell +, the exact same scenario happens with Ignis/Glacies, but the attack far more reliably gets kills even on bulky enemies. After that, Ignis vs. Glacies depends on the boon and refine chosen above.
The above scenario happens thanks to Vengeful Fighter's cooldown charge. In addition to acting as Quick Riposte 5, it also functions at granting you another action to furthr charge your special meter when your attacks respond to the enemy. It does not work like Steady Breath, the enemy attacks will not grant 2 charge, only yours.
A Skill: Distant Counter makes this build work. It allows Lissa to respond to mages and archers, and hit them back hard. The above Aether and Ignis scenarios are far mroe reliable since the best mages and archers in the game will all double Lissa and all have poor defense.
C Skill: Finally, as per usual, the C Skill is entirely team-dependant and heavily variable. In any mixed team of any sort, Atk Tactic 3 is the best option since Lissa has no need for the attack so much as other boosts like Def Tactic 3. In a non-mixed, non-armor team, Atk Smoke 3 or Atk Ploy becomes an option for a team lacking in -Atk debuffs, but if your team has those Spd Smoke 3 becomes the next alternative, then Spd Ploy, then which deensive Ploy is needed next. In a non-mixed team with ample debuffs,Hone Speed becomes preferred, as she will lielly be the only unit needing none of it. Due to their nature, unlike the rest of the build, these are simply add-ons t bolster everyone's effectiveness, not just yours.
In an Armor team, things are far more straightforward. You have 3 choices: Run an offensive, defensive, or hybridized armor team. In a defensive armor team, you have 4 Ward Armors which is very simple. In a hybrid team, Lissa is likely your green tank, and thus can run Armor March as chances are she'll have an armored mage or player-phase armor(Arden, Brave Axe Chrom,BRave Lance Effie, Wo Dao Draug are some examples) taking cover, and they'll want to use her as protection until she can swap them in to dive on an enemy with Cavalry-esque range. In an offensive armor team, she is still taking Armor March, but in this case you likely do not want to be using this builds as she will be supported with less useful Goads in place of Wards, and she performs better with a Brave Axe when Goaded.