AI Behavior Guidelines Shin Megami Tensei: Persona 3 FES

For all those complaining about the AI, I'm making a guide about what each Tactics do. They're listed in priorities order, meaning if both no.1 and no.3 have their conditions fulfilled, it will prioritize no.1. Please note that this is based on my personal analysis, and not completely right.

Also, knocking down with spells mean by Agi/Bufu/Zio/Garu only, not Hama and Mudo, since those don't knock enemy down. Null an element means either null/reflect/absorb.

~Act Freely~
The AI can do anything while in this Tactic. Due to the sheer unpredictability, using this Tactic is heavily discouraged for difficult battles.

1. If there is an enemy that can be killed with normal attack, it will use a normal attack against that enemy
2. If more than one ally is in bad health, it will use party-healing spell. If don't have, it will use a single target healing/item on the one with lowest HP.
3. If an ally is in bad health, it will use a healing spell. If low on SP or don't have any, use a healing item instead.
4. If there is an enemy tweak to an element, it will cast that single-target spell to that enemy.
5. If no enemies can be knocked down with weaknesses, it will proceed to do multi-target attacks (if enemy >1) or the most damaging attack (if enemy = 1).
6. Unknown conditions : Ailments healing, Ailments spells, Spirit Drain, Charge skills, Mudo and Hama spells.

The AI will never : Use buffs/debuffs.

~Knock Down~
In this Tactic, the AI is determined to put every enemy into 'Down' status. Due to the effectiveness of All-Out-Attack, this is probably the best Tactic to use in random battles.

1. If an enemy is weak to an element, it will use a single-target attack of that element.
2. If no enemies are weak to any attacks available, use a physical attack hoping to score a critical.
3. If the enemies null every attack available, even the physical attacks, and there is an ally in bad health, then use a healing spell/item. (Party healing if more than one ally. if not available, priority to one with lowest HP)
4. If there absolutely nothing to do, then wait.

The AI will never : Attack a Down'd enemy, using a spell that don't knock the enemy down, use a multi-target attack*, use buff/debuff.

*There is an exception for Aigis. In some parts of the game, Aigis will have Heat Wave as one of her skills. Heat Wave is multi-target strike-element, and the only strike skill she has at that time. Against strike-weak enemies, she will use this skill to knock them down, even if it means attacking the other down'd enemies, getting them back up again.

~Full Assault~
In this Tactic, the AI will focus on dealing the highest possible damage.

1. If there is an enemy that can be killed with normal attack, it will use a normal attack against that enemy
2. If there is an enemy weak to an element, it will cast a single-target spell to that enemy.
3. If an enemy's weak to Hama/Mudo, use a single-target skill to that enemy.
4. If no enemies are weak to elements available, then use the skill that will do the most damage. The AI will prioritize multi-target skills if enemies are more than one.
5. If the enemies nulls everything, then use a random non-damaging spell (Charge skills, Spirit Drain, etc) or do nothing.

The AI will never : Use buff/debuff, heal allies, cure ailments
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Male puppy is the biggest jerk of all animals because he is such a son of a female dog.

~Heal/Support~
In this Tactic, the AI will prioritize on supporting the party, only attacking when everybody's good and healthy. This is also the only Tactic where the AI will use buffs/debuffs.

1. If more than one ally is in bad health, it will use party-healing spell. If don't have, it will use a single target healing/item on the one with lowest HP.
2. If an ally is in bad health, it will use a healing spell. If low on SP or don't have any, use a healing item instead.
3. If everybody is in good health and there are buffs/debuffs available, then use buffs/debuffs.
4. If everybody is in good health and an enemy is on the verge of dying, then finish that enemy off using normal attack. If normal attack is nulled, then use a skill.
5. If everybody is in good health and an enemy is weak to an element, then use that single-target elemental skill.
6. If everybody is in good health and all attacks are nulled, then use a Break skill.
7. If everybody is in good health, then use the strongest attack available.
8. Unknown condition : Cure ailments

~Conserve SP~
The AI will try not to use SP.

1. If an ally's in bad health, then toss a healing item.
2. If the enemy don't null physical attacks, use the strongest physical skill.
3. If an enemy nulls every attack, then do nothing.
Unknown condition : Use a status-curing item

The AI will never : Use any skills that consume SP.

~Attack Fallen~
The AI will prioritize to defeat down'd enemies. Never used this Tactic, so don't know much. From what I've heard, though:

1. If there is a down'd enemy, then use the strongest attack to that enemy.
2. If there is none, then attempt to knock an enemy down either by critical or by weakness.
Don't know the rest. As I've said, I've never used this one.

~Stand By~
The AI will always Wait.

1. If inside battle, use the 'Wait' command.

The AI will never : do anything else.


I hope this helps

Good.


Mind charge can be used more often in full assault than you indicate. I think there's random chances involved; because if you have mitsuru full assault a target with no special reaction to ice, sometimes she uses bufudyne without mind charge, and sometimes she uses mind charge.

I'm pretty sure the "bad health/good health" cutoff is higher for heal/support than for act freely.

Also, while you are right that hama and mudo type skills are never used in "knock down", they do in fact "knock down", in that you get "1 more!" if you kill a weak target with an instakill skill of the corresponding element.

So curing ailments is the lowest priority and you are still defending the AI?

[This message was deleted at the request of the original poster]

When set to heal/support, ailment curing seems to be higher priority than buffs/debuffs. I think it has pretty high priority on act freely as well.

Mudo skills are treated the same as elements if the enemy is weak against them. I expect it is the same for hama, but I never use Ken. If no weakness can be exploited Koromaru will favor agi skills, but if left on act freely he will sometimes still use mudo.

not Hama and Mudo, since those don't knock enemy down

They do, actually. Try putting on a Persona with Endure and let yourself get to 1 HP through a successful light/dark attack, you'll be knocked down.

Unless I'm being fatally wrong.

They do, actually. Try putting on a Persona with Endure and let yourself get to 1 HP through a successful light/dark attack, you'll be knocked down.


I don't know about Endure, but with a Homunculus, you'll be knocked down if you were weak to the attack (if you weren't, but it killed you anyway, no knockdown).

Interestingly though, in this situation, a second "weak" instakill (also blocked by Homunculus) doesn't make you stand up, as would happen if you were hit by "weak" when downed normally.

I must be interpreting TC's posts wrong then. So their actions weren't posted in order of priority? Either way there's nothing that can convince me that the AI isn't stupid. Maybe if your characters are really high leveled you won't encounter any problems but when I played hard mode I encountered plenty of AI stupidity.

Scanned and unscanned will alter AI behaviour.

On Knock Down tactic with scanned enemies,
i. Light/Dark user will use Light/Dark against Light/Dark-weak enemies.
ii. ST spells are favoured over Target: All spells mainly due to higher accuracy.