Loki’s trickery has ensnared us yet again, and spawned the dreadful Chaos Season, with new rules and restrictions. Fortunately, we can all get help to understand it.
In standard Aether Raids seasons, Mythic Heroes provide benefits to Lift as well as stats: Light and Astra Mythics provide extra offense lift in their season when used on a Raiding Party with units Blessed in their element, as well as providing +1 Lift gain per merge on the mythic. Dark and Anima Mythics reduce the lift on a Defense loss in their season when they are used on a team with units Blessed in their element. All of these effects are disabled in Chaos season; Mythics do not provide any extra lift gain on an offense win or reduce lift loss on a defense loss. The only exception to this is that the bonus Defense mythic, which is Yune this season, reduces the lift on a defense loss by 20. While you are free to use Offense Mythics on a Defense team, the bonus Offense mythic does not reduce lift loss when used on a Defense team, even in Chaos Season.
Mythic Heroes and Legendary Heroes normally also provide stat boosts to Heroes blessed with a corresponding element, so a Light Mythic like Eir provides a boost of +5 HP and +5 Res to any Light-blessed Heroes when used in Aether Raids in Light Season. All of these stat boosts are also disabled during Chaos Season.
Likewise, some Mythic Heroes such as Reginn can unlock an extra unit slot in their corresponding season, the 6th team slot for Astra and Light, and the 7th team slot for Dark and Anima. This effect is also disabled during Chaos Season.
To compensate for the loss of Mythic scoring, the Lift values have been altered. The base Lift lost on a defense loss is 60 lift, reduced by 20 for each successful KO. The base Lift gained on an offense win is 170, which is boosted further by 20 for including a bonus unit, and an additional 20 for getting at least one KO with a bonus unit during the match. The extra 10 lift gain for winning a match with no units lost in Vault of Heaven is still in effect. In addition to this, the pool of bonus heroes has been expanded; this season all Heroes released in Version 1 of Fire Emblem Heroes are eligible as bonus units, in addition to the 9 standard bonus units. So players have many more options than usual.
Chaos Season also comes with new restrictions on teambuilding. Both offense and defense teams are now restricted from including more than one unit with Dance or any variation of it, as well as no more than one unit with a Savior skill like A/R Far Save or A/D Near Save.
In addition, no duplicate Heroes can be used on the same team during Chaos Season. Specifically, this refers to any Heroes that can be merged; Heroes with the same name and the same epithet. So, for example, you cannot use two Eirika - Pledged Restorers, but are free to use one Eirika - Pledged Restorer and one Eirika - Twin Refulgence.
There are no Bronze, Silver, or Golden Thrones awarded in Chaos Season.
Recommendations and Speculation
As this is the first ever Chaos Season and we are only a couple days into it, the meta has not stabilized and is currently somewhat hard to observe. However, there are a few things we can say about what is viable and valuable compared to normal Aether Raids.
The first big change is that without Mythic Heroes affecting Lift gain, players are now free to use almost any Hero on either offense or defense with no real drawbacks. So Defense Mythics like Medeus can now be used for Offense, and Offense Mythics like Elimine can now be used for Defense. Likewise, Legendary Heroes such as Legendary Sigurd can be used regardless of whether their Element is currently active.
The lack of stat boosts from Mythic Heroes also affects the viability of some teams and units. For example, on an Offense team, it was previously very easy to get +15 or +20 HP as well as boosts to other various stats simply by including 3 or 4 Mythic Heroes of the correct element. This made tank units like Brave Hector or Valentine’s Gustav significantly harder to KO in some cases. The boost on Defense teams was not quite as drastic, usually +10 HP for two mythics, +15 HP for three, but the lack of this boost means that Heroes on a Defense team are now that much more vulnerable to being KO’d by strong offense units. This buffs some strategies that rely on this high damage like Hit and Run and Vantage while somewhat nerfing Tanking.
The ability to use any Mythic Hero also means that you can bring out any counter to a particular unit or team you have access to. For example, Canto teams are somewhat stronger than they already were due to powerful units like Brave Eirika and Eitri being able to more easily KO units on a Defense team when they have 10 or 15 less HP and possibly less Def or Res as well. This means that units like Medeus with Canto Control may be more valuable as a check to those strategies. In addition to this, Medeus also blocks the out-of-combat damage from the Bolt Tower, making him perhaps the single strongest Defense Mythic in Chaos Season and very valuable on any team that is vulnerable to having units picked off by mobile threats with Canto, or being weakened by the Bolt Tower to the point where multiple units on the team can be KO’d by a unit using Vantage.
Due to the limitations on Savior units as well as the lower bulk of Offense units, teams that rely on extremely high threat range to KO units are arguably buffed by Chaos Season. For example, the “Cav Line” was once a popular defense team archetype that involved placing several ranged cavalry Heroes on the lower of the two starting lanes. Since ranged cavalry can move 3 spaces and attack units 2 spaces away, they can threaten the map tiles that the offense units start in within the same lane. These teams were once very difficult to react to and defeat without preparing particular counters, since they gave the offense player so little room to maneuver. However, the rise of Savior skills, as well as extremely powerful support units like Elimine, has allowed tanks like Brave Hector and Ascended Fjorm to shrug off most attacks even from several cavs in a row. In Chaos Season, these tanks are deprived of some of their statistical advantage from Mythic Heroes, and it is also impossible for offense teams to use both Near Save and Far Save units on the same team. These rules may make teams like the cav line more viable.
Lastly, it is important to remember that you gain 20 extra lift on offense for winning a game with a team in which you got at least one KO with a bonus unit. So on every team, you should make sure to include at least one of the many options of bonus unit that you think you can get at least one KO with, and consider this when previewing a map before choosing which team to bring against it. While this may feel somewhat artificial, it is important to scoring as well as you can within the rules of Chaos Season.