Understanding this game's AI

[Redwall]

How much is known about this game's AI? I've been playing the earlygame and feeling a bit confused about what the AI prioritizes in its decision-making.

Is there a team in "I"?

After hearing from XeKr that a five-turn clear of Lunatic C3 could be done with an 8-Def Corrin, I rigged myself a strong Corrin and tried placing Jakob (7 Def) and Gunter on the top half of the bottom bridge to KO an Archer, and found that the Samurai targeted Corrin, and not Jakob like I expected (which would have ruined that five-turn clear since the Archer could have moved to initiate a near-fatal Dual Attack). This is consistent with the idea that the AI does not search for fatal combinations of individual attacks, let alone fatal combos involving Dual Attacks, during the enemy phase.

I have wondered if the order in which enemies attack (which arguably matters more than ever because of Dual Attacks) can be determined in a way similar to what we saw in FE12--highlighting an enemy and cycling through all the others with the L button. However, I've seen at least one case in Fates where the AI broke this L-sequence to deliver a DA that wasn't fatal, so I'm not quite sure what to think.

Passing up big damage

On PP1 of Lunatic C5, I placed Corrin and the Kaze/Rinkah pair so that each was in range of both the Wyrmslayer Mercenary and the Dark Mage, with Corrin in clear danger of getting killed during EP1 from the two enemies ganging up on her (Kaze had enough Res to survive).

You might have expected EP1 to feature the Mercenary attacking Corrin, who would've eaten 20 damage at 77% displayed hit, but he instead attacked Kaze/Rinkah for 10 damage at 74% displayed Hit, something that wouldn't have happened in, for example, FE12. I assume the Mercenary did this because Corrin was capable of OHKOing him back during EP1, and Kaze wasn't.

[Tooru]

I assume the Mercenary did this because Corrin was capable of OHKOing him back during EP1, and Kaze wasn't

This.

They will try not to be ORKOed if there are other targets to attack.

I am not sure but it seems that they will also try not to be ORKOed by critical.

[Tribute]

This.

They will try not to be ORKOed if there are other targets to attack.

I am not sure but it seems that they will also try not to be ORKOed by critical.

FWIW on the pot chapter on conquest I had 2 samurai who started the turn adjacent to Effie actually just up and pass rather than break themselves on her

[eclipse]

The AI will not attack anyone that they can't damage, even if they have offensive skills like Lunge/hidden weapons that can otherwise drop their opponent's defensive parameters. Wound up exploiting this on Chapter 17 Nohr.

[Tooru]

FWIW on the pot chapter on conquest I had 2 samurai who started the turn adjacent to Effie actually just up and pass rather than break themselves on her

For most enemies, if they cannot damage you while you can countattack them, they will ignore you.

But in Ch25, Ninjas will try to attack you even when the damage is 0 and you will beat them by counter.

[GoXDS]

The AI will not attack anyone that they can't damage, even if they have offensive skills like Lunge/hidden weapons that can otherwise drop their opponent's defensive parameters. Wound up exploiting this on Chapter 17 Nohr.

it seems to depend. on that same chapter, I had Effie paired and they refuse to attack her. unpaired, they still did 0 but attacked. it may have to do with the AI seeing that one of the 2 Samurai can dmg her (one had Quick Draw) but they don't always select that Samurai as the Support so it's weird

[eclipse]

I'm moving slowly through Nohr (and by slowly, I mean I took 49 turns on Chapter 17), so I'll see what else influences AI, besides having a swarm of ninjas near Xander, all doing a whole lot of nothing. I'm on Hard Classic, if that's any help.

[Tooru]

it seems to depend. on that same chapter, I had Effie paired and they refuse to attack her. unpaired, they still did 0 but attacked. it may have to do with the AI seeing that one of the 2 Samurai can dmg her (one had Quick Draw) but they don't always select that Samurai as the Support so it's weird

Was Effie using Javelin?

[FEF]

Hold on now, enemies will gladly attack you at 0 damage with lunge. I've seen it several times.

I'm pretty sure there are simply several AI routines in the game - some enemies, for instance, still suicide me when they do 0 damage. Some ignore me entirely. Others run up to me, and then refuse to actually attack.

[eclipse]

I have yet to run into the zero-damage suiciders - but that could be because I'm not far enough into the game yet. Didn't really notice this issue in Hoshido, but it could be because no one there could wall like Xander.

[Tooru]

Hold on now, enemies will gladly attack you at 0 damage with lunge. I've seen it several times.

I'm pretty sure there are simply several AI routines in the game - some enemies, for instance, still suicide me when they do 0 damage. Some ignore me entirely. Others run up to me, and then refuse to actually attack.

Was your unit using 1~2 weapons like Javelin? I don't think they will Lunge you if you can counterattack.

[1% critted]

The AI doesn't know it has poison skills. Let's say Silas is in range of two poison strike faceless and Elise is in range of one of them. If they both attack Silas he'll die due to poison strike doing more damage than actually displayed, but since the AI doesn't know that, one of the faceless will attack Elise and the other will attack Silas.

As mentioned before, if an unit will do no damage, and will be counterattacked it won't attack. In some cases, it also won't move if the only unit in it's range is invincible. The exception to the rule is that the AI sometimes (I'm still not sure about this one) will attack with 0 damage even with counterattack if your unit has a full dual guard gauge, just to get rid of it. The reason why I say i'm not sure about it, is that you can bait one-shot attacks first on EP (say a bow vs. a flier) with a full dual guard gauge. Example: if Camilla with a pair up with dual guard ready is in range of a Kinshi knight and a Lance Master, but the Kinshi knight will one shot her, the Kinshi will move first to try to kill Camilla, but will fail due to dual guard.

I have more of these, but I can't remember them right now. Will post more later.

[Aggro Incarnate]

I recall that at least in Conquest Hard and Lunatic, the enemy AI will not attack if it deals zero damage; this probably isn't the case for all routes, all difficulties since I remember it being otherwise in Birthright Lunatic.

I'm not sure as to what extent enemies with stat seals, HP-reducing skills, or position-changing skills are an exception though

[joshcja]

Hold on now, enemies will gladly attack you at 0 damage with lunge. I've seen it several times.

I'm pretty sure there are simply several AI routines in the game - some enemies, for instance, still suicide me when they do 0 damage. Some ignore me entirely. Others run up to me, and then refuse to actually attack.

Im pretty sure the AI actually varies based on victory objectives, the map itself, and the movement routine/aggro of the unit. And frankly im pretty sure quite a few enemies have genuinely custom AI.

if you want a good place to play with "standard" enemy AI ch13 is a pretty good sandbox.

Edited March 5, 2016 by joshcja

[XeKr]

How much is known about this game's AI? I've been playing the earlygame and feeling a bit confused about what the AI prioritizes in its decision-making.

Is there a team in "I"?

After hearing from XeKr that a five-turn clear of Lunatic C3 could be done with an 8-Def Corrin, I rigged myself a strong Corrin and tried placing Jakob (7 Def) and Gunter on the top half of the bottom bridge to KO an Archer, and found that the Samurai targeted Corrin, and not Jakob like I expected (which would have ruined that five-turn clear since the Archer could have moved to initiate a near-fatal Dual Attack). This is consistent with the idea that the AI does not search for fatal combinations of individual attacks, let alone fatal combos involving Dual Attacks, during the enemy phase.

I have wondered if the order in which enemies attack (which arguably matters more than ever because of Dual Attacks) can be determined in a way similar to what we saw in FE12--highlighting an enemy and cycling through all the others with the L button. However, I've seen at least one case in Fates where the AI broke this L-sequence to deliver a DA that wasn't fatal, so I'm not quite sure what to think.

Passing up big damage

On PP1 of Lunatic C5, I placed Corrin and the Kaze/Rinkah pair so that each was in range of both the Wyrmslayer Mercenary and the Dark Mage, with Corrin in clear danger of getting killed during EP1 from the two enemies ganging up on her (Kaze had enough Res to survive).

You might have expected EP1 to feature the Mercenary attacking Corrin, who would've eaten 20 damage at 77% displayed hit, but he instead attacked Kaze/Rinkah for 10 damage at 74% displayed Hit, something that wouldn't have happened in, for example, FE12. I assume the Mercenary did this because Corrin was capable of OHKOing him back during EP1, and Kaze wasn't.

For Dual Attacks, the AI will specifically move (breaking enemy order) to act as the supporting unit in dual attacks if the supporting unit can’t actually attack anyone that phase themselves. They don’t recognize Guard Stance, so they’ll attempt this even if it doesn’t actually increase damage (it should still increase their hit rate by 10 I think...).

If that enemy can initiate an attack themselves that phase, then I don’t think they move specifically for dual attacks, and any that occur (usually combinations of 1 and 2 range units) are coincidences of enemy order. For example in the C3 case, it might be possible for the remaining Archer to move first and hit Jakob with Myrm attack stance, then Myrm hit Jakob with Archer stance for the ko, but the AI isn’t quite that smart. It goes, both the Myrm and Archer will be attacking this turn, and the Myrm is supposed to go first. He chooses Corrin because his sword does less damage to Jakob and his Dagger. If Corrin’s Def is low enough to die to the archer (<8, no Hp Boon), the Archer then sees a kill opportunity and goes for Corrin. Otherwise, he hits Jakob as he does more damage.

In your C5 Kaze case, isn’t it just because Merc+Dark Mage kills Kaze anyway? The AI is good about finding the obvious fatal combinations (again the whole reason Corrin needs 8 Def is so the Merc+Archer combination isn’t fatal), and maybe that one it found first. (edit: If your Kaze can survive the Merc+Dark Mage and Corrin is also in range, I'm pretty sure the ai will go for Corrin. Is that situation easily possible with Hp tonic/Sakura aura?)

The AI might have some of a self-preservation inclination but they generally still attack those it hits harder.

In Conquest, the AI does tend to not attack if it can’t damage your unit.

Edited March 5, 2016 by XeKr

[Dark Holy Elf]

I have absolutely seen ninjas attack doing 0 damage, but only if the defence-lowering would be immediately useful to another ally of theirs on the same turn, for what it's worth.

[Abysswalker25]

If the enemies have Lunge, they will use it to drag you closer to their forces to swarm you. And they WILL chain lunge together if they can to serperate your units as far as possible. And if they do 0 damage to you, aside from Ninjas you can just kill them. It is hilarious and made chapter 23 super easy because no one tried to attack Xander and he killed them all freely.

[Radiant Dragon]

Regarding the 0 damage, I believe enemies will only attempt this if they have have a Shuriken or other stat-decreasing weapon and won't take any damage from a possible counter attack.

In Ch.17 on Conquest, I would send Gunter up north to fight the one Ninja up there (after activating the Dragon's Vein), and it would never move to attack him on the Enemy Phase, until on one attempt I forgot to move Gunter's Javelin to the top of his inventory, and on that run the Ninja did attack Gunter for no damage. Meanwhile in Ch.10, the Oni on the right with the Throwing Club wouldn't attack Effie if he couldn't deal damage to her, even though she had an Iron Lance equipped.

Another thing I've noticed is that the AI doesn't always immediately go for an easy lethal attack even if there's no Guard Stance or skills to stop it. In Awakening, if the AI had a lethal combination of damage on one of your units, they would ignore their predefined turn order to take it, but I haven't seen that in Fates yet. I don't remember specifics for this one, but I know that I've had a unit in OHKO range of an enemy later in the turn order at least a couple times, but that unit won't move until it's his/her turn.

[1% critted]

Another thing I've noticed is that the AI doesn't always immediately go for an easy lethal attack even if there's no Guard Stance or skills to stop it. In Awakening, if the AI had a lethal combination of damage on one of your units, they would ignore their predefined turn order to take it, but I haven't seen that in Fates yet. I don't remember specifics for this one, but I know that I've had a unit in OHKO range of an enemy later in the turn order at least a couple times, but that unit won't move until it's his/her turn.

I don't know if my messages don't show up or something , but they do go for the easy lethal attack, even if Dual Guard will stop it. Try having a full Dual Guard Camilla in range of an aggresive Kinshi Knight, and it will move first and go for the kill. I tested it on Veloria's paralogue against an Adventurer, and it worked.

[GoXDS]

I don't know if my messages don't show up or something , but they do go for the easy lethal attack, even if Dual Guard will stop it. Try having a full Dual Guard Camilla in range of an aggresive Kinshi Knight, and it will move first and go for the kill. I tested it on Veloria's paralogue against an Adventurer, and it worked.

the Adventurer may be higher in the turn order. in that same Paralogue, I've seen units left alone for a few attacks even when within kill range

[1% critted]

I guess more testing will be required, but I've manipulated the AI before with that trick.

[Radiant Dragon]

Yeah, the AI isn't consistent about it, which leads me to believe that only certain AI behaviors will ignore formation to do so and some will not. It might depend on route, though? A slightly different example here, but I think I remember enemy Cavaliers on Ch14 in Birthright were more than happy to break their weapons against Scarlet's Defense despite not being able to do damage to her, which I'm sure wouldn't work on Conquest.

[nflchamp]

Some enemies definitely favor surviving even over taking a kill shot, but I'm pretty sure that's only if they have a healer to retreat towards and are heavily damaged. I remember being prepared to reset in Birthright's ninja chapter as a half-dead ninja should have had the damage to finish off Hayato easily, but instead retreated back towards the healers.

[Radiant Dragon]

I noticed injured enemies running towards the healer in Ch17 Conquest as well, but I don't think I had anyone in range of dying at that point so I can't say what they would have done in that instance.

NPC's will also hang around player units with staves to get some healing if they're injured. I had a 1HP Frederick clinging to Elise for a couple turns in Before Awakening after his bout with those Ninjas.

[Byleth]

What I know is, the AI will hit people who can take higher damage from them even though their hit is very low. I've tested it in Boo Camp DLC where in enemy range I have debuffed Asugi with 9 Def, 41 Spd, Barb Shuriken Equipped, full Guard Stance bar and Midori with 17 Def, 23 Spd with Iron Bow Equipped no Guard and the Enemy chose to hit Asugi instead.