Team building for Arena defense is an entirely different process when compared with team building for Arena offense. This is mainly because you won't be wielding your Arena defense team - the game AI will do it for you. Because the AI is deterministic and easy to manipulate, players facing your Arena defense team will have a huge advantage as they will get to set the fight's rhythm, not the AI.
An Arena defense team's goal (normally) isn't to win most of the fights it's involved with.
Indeed, the scoring system does not reward multiple successful defenses - netting a single perfect defense will yield maximum score for the ongoing Arena season.
Instead, an Arena defense team's goal is to land at least one perfect victory over the course of each Arena season.
There are two ways to achieve a perfect victory: player forfeiture and total annihilation with minimal losses. As total annihilation is basically never going to happen against high-level players, player forfeiture is the more likely scoring source for defense.
Player forfeiture happens because giving up a failed match (i.e. a match where at least one unit was lost by the attacking player) consumes less resources than winning it. Giving up immediately breaks the scoring chain, which means the next Arena battle will occur in a new, clean scoring chain. On the other hand, keeping on fighting after losing an unit will keep the scoring chain going with a suboptimal score, which most high-level players don't desire.
Thus, your main goal when building an Arena defense team will be to have said team break attacking players' scoring chains by landing kills while under the AI's control. Forget about building balanced teams you'd actually want to wield for Arena offense, you're aiming for fluke kills and this means running fluke teams you wouldn't want to face in Arena offense.
There are two main strategies to score fluke defensive kills - either run a team so powerful its opponents will have a hard time safely taking it out (sheer power team), or run a team with gimmicky units specialized to target a couple units common in the meta (gimmick team).
Sheer power is relatively straightforward in terms of unit selection. Pick differently colored units among the EX-level and A-level threats, and you have a team (doubling the green slot is probably a good idea in the currently blue Arena offense meta). If you can't fill all four slots, go for a gimmick team instead.
If you have the resources for it, consider building the units you've picked for defense (this usually means picking different skills, especially B slot - Quick Riposte, Vantage, Breaker skills (especially Swordbreaker and Green Tomebreaker) are good picks as they make fluke kills more likely to happen). Prioritize building EX-level units here, as they're more generally threatening.
Gimmick teams, unlike sheer power teams, aren't really concerned with balance. Pick a couple frequently played units of two different colors and build your entire team around killing them. Run specialized units and skills - this is the time to be monomaniac in your team and unit designs.
One example of gimmick team (focused on killing Effie and Nino) might be Swordbreaker Sanaki + Green Tomebreaker Julia + Lancebreaker Hammer Frederick + Ruby Sword Olivia (Olivia can help other units land fluke kills against careless players).
The AI is deterministic. This means attacking players get to game it, but nothing's keeping you from laying a few manipulations of your own in your units' Assist slots.
Specifically, the AI will always use available Assists if there's no foe in range. This means you can trick your units into staying close to each other by having them all run Assists. For one simple example, giving half your units Pivot will produce harder-to-predict movement and may take careless players by surprise, forcing them into suboptimal attacking strategies.
The best way to observe how the AI plays with the tools it's given is to have your team play in auto mode - presumably, this AI functions similarly to the defense AI.
Make sure to also run one or two Rally assists too - especially Rally Spd as this can change their recipient's speed tier.
- An anti-Nino anti-Effie gimmick team.
- Sanaki: Triangle Adept + Swordbreaker.
- Swordbreaker allows her to blast sword users into oblivion as a side-job.
- Julia: Green Tomebreaker.
- Frederick: Lancebreaker + Hammer.
- Olivia: Ruby Sword (doesn't need to be Ruby Sword+).
- Ruby Sword is mostly a defensive asset here, although it can certainly serve should an Hector enter Olivia's danger area.
- Sheer power team based on dual-range counter and Kagero's anti-infantry Poison Dagger+.
- Ryoma: Defiant Atk + Vantage.
- Nowi: Triangle Adept + Quick Riposte.
- Hector: Distant Counter + Vantage.
- Kagero: Green Tomebreaker.
This article is part of the General Team Building Guide, a series of articles written by takaminacchan. A list of the articles in this series can be found at the top and bottom of each article.