Last Updated on April 21, 2022
How does battle actually work in NieR Reincarnation? Let’s take an in depth look at what’s actually going on and how you can affect it.
Here is a screenshot of battle, color coded and with text labels:

On the very left you will see a list of enemies with their elemental affinity. Tapping on the enemy in the list will target them. You can also tap on the enemy itself in front of you to target.
At the very right is the companion list skill. Tapping on it will open the menu of companion skills. The order of companion skills depends on the loadout placement, from left to right.
At the bottom are the characters in battle. There is their character skill, a line around their portrait which is a gauge. The gauge charges as damage is taken and received. Then there is their elemental affinity (dependent on the primary weapon equipped) and HP bar. Right next to the HP bar is the two weapon skills (also dependent on the primary weapon equipped). Below the character portrait will be a list of current status buffs and/or ailments.
On the top right is the speed up button, the Auto button (to toggle weapon/character/companion skills being automatically used), and the Menu button. Under that is the wave you’re currently on and how many total waves there are in that specific battle.
The character in the middle of battle can be moved around by dragging the character across the screen – this doesn’t seem to have an effect on the actual gameplay.
Auto Battle and Hit Chains
Regardless of whether the “auto” button on the top right is activated or not, basic attacks, dodges, and counters are all automated.
At first, using auto will only use weapon abilities. Clearing main quest Chapter 6 on hard difficulty will unlock Auto+, which will have auto also use the character and companion abilities.
If a character has a preferred weapon equipped, they will chain anywhere between 1-5 basic attack hits. If they do not have a preferred weapon, they will only perform 1 hit.
Character Skill Gauge
Every character has a unique skill. The gauge level of that skill determines the initial speed of that skill charging. From slowest to fastest, it goes A>B>C.

Character and Weapon Passive Abilities
Characters have two passive abilities, and weapons have two passive abilities. Let’s take a look at some of them mean and how they affect battle. The degree to which these character passives are strengthened rely on character ascension. Please be aware this is not an exhaustive list, as more abilities may be added over time.
The degree to which weapon passives are strengthened rely on using specific materials related to that specific weapon in the Skill tab. Also, you unlock a weapon’s second passive by evolving the weapon, and increase the level cap of the passive by ascending the weapon. These abilities are great boons for battle, so make sure to enhance them.

Aegis
Defense up

Ambush
Critical rate up

Caged Vigor
Damage up by a specific percentage when HP is below a certain threshold

Fleetfoot
Agility up

Haste
Skill cooldown reduction

Pursuit
Damage up on chain attacks of 3 or more.

Toughness
HP up

Training
Increases chance of normal attack being 3-chain or greater

Vigor
Attack up
Status Ailments

Status ailments can be inflicted during battle, either by the player or the enemy. Here’s what each of them do:
Poison – Continuous damage over time
Stun – Prevents user from taking any actions for a short time
Blind – Makes attacks more likely to miss
Burn – Continuous damage over time
I hope this helps you understand what happens during battle in NieR Reincarnation. You can check out more guides here.