Performing Inigo

Preferred IV: +SPD / -RES

• Most of Inigo's actual combat will take place in the enemy phase, so having a boost in defensive speed will certainly do him some small but handy favors. HP and Defense Assets are also slightly admissible for slightly better tanking.

• The build is specialized against colorless bows and daggers rather than blue magic, which Inigo doesn't tank exceptionally well even with Triangle Adept. A Flaw in Resistance is therefore preferred, though HP and Def are nearly as acceptable.

Weapon: Gronnraven+ 

• Gronnraven provides general weapon triangle effectiveness against colorless opponents, especially most bow units not named Legendary Alm (Please. Don't try to push it.).

Assist: Dance

Special: Moonbow / Luna

• Inigo's low base stats and limited combat usage basically limit him to short Specials that rely mainly on opponent stats, which basically boils down to Moonbow. In most fights with a weapon breaker skill versus non-Null Follow-Up targets, Inigo can activate Moonbow in a single round. 

• Luna is marginally acceptable for better burst damage at a higher cooldown; in practice, Inigo can handle at least one successful round of combat and save his Luna-charged attack for other foes or a particularly persistent target.  

Passive A: Triangle Adept

• The other half of the Triangle Adept + Raven tome combination, this is used to magnify Gronnraven's effectiveness against colorless and blue foes. Inigo should not, however, invest full faithfulness of it against extremely powerful attacks (such as Dire Thunder or Ophelia’s Missiletainn).

Passive B: Bowbreaker / Wings of Mercy / Daggerbreaker / Null C-Disrupt

• Bowbreaker specializes Inigo against colorless bow units by granting a follow-up attack while limiting these foes to only one attack per round. This helps make up for Inigo's otherwise lack of offense; otherwise, he is usually only able to perform one attack against most competently fast archers.

• Wings of Mercy is a basic yet widely recommended skill on most dancers, and Inigo is no exception as he gains the ability to Dance any badly damaged teammate from afar. 

• Due to a surge of weapon refinery options (i.e. Kagero) and new, competitively viable dagger units (i.e. Summer Ursula and Sothe), Inigo can use Daggerbreaker instead if it suits the needs of your barracks or team.

• Null C-Disrupt is a mostly Aether Raids-specific option against staff units who utilize Dazzling Staff in any form, as well as bow units using Firesweep Bow. Using it allows Inigo to soft-check Veronica, Lyn, and other similar units without needing to use said skill on your usual carry units. The skill, however, is very expensive and rare to come by, and Inigo loses the precious utility of other B slots like Wings of Mercy. 

Passive C: Infantry Rush / Infantry Flash / Atk Tactic / Player Preference

• Infantry Rush is an affordable but handy skill that allows fellow infantry units within two spaces to essentially gain Heavy Blade without needing to use that in their A or seal slot. This is also likely to free up the teammates' seal, giving them an opportunity to use conventional options such as Brazen Atk/Spd 3. 

• Infantry Flash can be used in the same vein as Rush, though it is significantly rarer as Rush can be acquired from Brady who is in the general pool, while Flash is limited to Legendary Marth at this time of writing.

• Atk Tactic combines both budget and power by offering a hefty +6 Attack boost to teammates, so as long as Tactic conditions are fulfilled.

• The C skill slot is otherwise up to player preference; recommendations include other Tactics or Hone skills. 

Sacred Seal: Any Chill Skill / Any Tactic skill / Distant Def / Quick Riposte / Player Preference

• A Chill skill seal of choice can be used to debilitate any opponent from afar with the highest respective stat. It can potentially benefit Inigo himself if the debuff hits his usual opponents.

• Likewise, a Tactic seal of choice can be used especially with Atk Tactic to further support a mixed movement team passively. 

• Distant Def and Quick Riposte get honorable mentions for improving Inigo's combat prowess. Quick Riposte, in particular, can be used with Null C-Disrupt to close in kills on colorless units that may otherwise survive a fight with him (due to a lack of weapon breaker). It can also expand Inigo's index of targets outside of his chosen weapon breaker. 

• The seal is otherwise open for player preferences.

Preferred IV: +SPD or +ATK or +HP / -RES

• Inigo's reliance on defensive speed holds true even at higher investment and merges. An Asset here therefore benefits in most practical cases.

• Inigo's Attack still isn't anything special, though damage-based tomes such as Gronnblade and Keen Gronnwolf benefit slightly from an Asset.

• HP can be considered as an Asset for specific HP-based skills and team setups.

Weapon: Gronnblade+ / Spectral Tome+ (+Spd) / Keen Gronnwolf+ (+Spd)

• Gronnblade is the best power-oriented weapon Inigo can use as it offers huge potential damage output. Though it seems counterproductive to use a support-reliant weapon on a dancer, there are plenty of skills (such as Joint Hone Spd) and methods for both Inigo's teammates and himself to benefit. 

• Spectral Tome is one of the better refinable supportive tomes Inigo can access; since many high-investment teams will rely on visible stat-boosting to apply pressure, the tome's Panic effect will turn the tables nearly instantly. However, it is seasonally limited by an armored unit you may be hard-pressed to fodder.

• Keen Gronnwolf is a more accessible alternative that hits an entire movement class effectively, giving Inigo a slightly more offensive presence. In Aether Raids, it can be used for emergency kills on the likes of Brave Veronica, Reinhardt, Brave Lyn, Brave Eliwood, etc. It sees limited use in Arena as Inigo should not be KOing enemies instead of a bonus unit in the first place.

• For scoring purposes, Inigo should use a refinable tome (most are fine besides the listed ones) in favor of Gronnblade as refined weapons like the former have a higher SP cost than the latter. Gronnblade also increases Inigo's risk of accidentally stealing kills from bonus units. 

Assist: Dance

• Dance is still as useful as ever, even moreso in high-investment Colisseum modes, where scoring requirements impose stricter movesets and positioning caveats on Inigo's teammates.

Special: Moonbow / Ruptured Sky / Blue Flame

• Even at high investment, Inigo's basic stats still hold him back from using anything other than opponent stats-reliant specials. Moonbow is basic but best as it ignores Inigo's otherwise middling power output at a low cooldown.

• Blue Flame and Ruptured Sky aren't exactly improvements compared to the more accessible and equally useful Moonbow. Their main use, rather, is to bolster Inigo's scoring potential with their high SP costs. 

• Notably, players inheriting Ruptured Sky from Female Byleth can also acquire Fury 4, another optimal skill.

Passive A: Fury (3 or 4) / G Duel Infantry / Bonus Doubler / Any HP skill

• Fury offers Inigo the best value of all A-slots as it directly adds much-needed defensive and offensive stats to Inigo's poor base statline. The recoil should not be much of a concern as Inigo will likely be minimally involved in direct combat.

• G Duel Infantry's main use is significantly increasing Inigo's Arena scoring, though the additional +5 HP comes in handy for certain HP-based skills and setups. 

• The best accompaniment for Gronnblade, Bonus Doubler bolsters any visible buffs Inigo has acquired and eliminates most worries of middling damage output. It makes him even more teammate-reliant than ever, however. Those using it should keep in mind Inigo should be providing his share of support.

• HP-based builds not used in Arena should instead use the basic HP +5, or any of its two-stat variants.

Passive B: Wings of Mercy / Windsweep / Any Chill Skill / Sudden Panic / Player Preference

• Wings of Mercy contains a ton of movement utility as Inigo can help badly damaged teammates from afar, while being one of his higher scoring options.

• Windsweep (or Watersweep if preferred) prevents counterattacks from slower units with Distant Counter, enabling him to fire off a single free hit. This can translate to a game-changing widespread Panic effect from Spectral Tome, or a simple strong attack from Gronnblade. 

• A Chill skill of choice can be used to help Inigo provide more support passively by inflicting debuffs on particularly tough units.

• Sudden Panic is yet another passive option Inigo can utilize by inflicting mass Panic on foes that are adjacent to each other. However, it requires a specific A slot and Seal setup to use properly.

• Player preferences yet again rule above all else, though other honorable mentions include Desperation, Null C-Disrupt, and Dance skills.

Passive C: Joint Hone Spd / Hone Atk 4 / Any infantry perk skill / Player Preference

• Joint Hone Spd benefits both Inigo and adjacent teammates by providing a meaty +5 Speed at the start of their turn. It is particularly beneficial with Gronnblade as it can be difficult for Inigo to acquire stat bonuses for himself without alienating his teammates' own C or seal slot skills. 

• Hone Atk 4 is the best Atk bonus Inigo can passively offer to his teammates.

• The player can take advantage of Inigo's vast array of Infantry-based C slots—including Infantry Rush, Infantry Breath, and Infantry Pulse—to manipulate his fellow infantry teammates' cooldown and free up their skill slots.

Sacred Seal: Chill Spd / Chill Atk / Atk/Spd Bond / HP/Spd 2 / Player Preference

• As with the B slot, Inigo can use a Chill skill seal of choice to debilitate superunits without needing to initiate directly himself.

• Atk/Spd Bond directly increases Inigo's offensive stats when adjacent to a teammate, and is further enabled by accompanying skills such as Wings of Mercy or Infantry Breath.

• HP/Spd 2 and other similar seals should be used in HP-based setups.

• The vast library of seals Inigo can run is ultimately up to the player.