The Units submode in Metal Slug Infinity is where the player can view and edit their collected units.
Grades and Promotion[]
The player deploys Regular Army units as well as various friendly enemy units due to the main cast accidentally transporting themselves to a parallel universe after destroying the Time Slug.
Units have various abilities that are unlocked by leveling up or promoting to raise its grade (number of stars). The color of stars represent the number of overall stars. After five yellow stars, Grade 6 is one purple star. Unit grade is increased by collecting a certain number of 
Unit Pieces or using 
Soldier Promotion Tickets.
| Grade | Stars | Unit Pieces/Tickets |
|---|---|---|
| 1 | 
|
10
|
| 2 |
|
30
|
| 3 |
|
60
|
| 4 |
|
100
|
| 5 |
|
300
|
| 6 | 
|
700
|
| 7 |
|
1300
|
| 8 |
|
2100 or 2
|
| 9 |
|
3200 or 3
|
| 10 |
|
4700 or 4
|
Unit Pieces are earned by clearing Dungeons, waiting in the Search & Rescue tab, rewards from events and missions, bought through the various Shops, and by purchasing Soldier Boxes at the store. Soldier Promotion Tickets are earned through events or bought at the World Boss store for 3,000 
Cores each.
Dungeon[]
The player uses six units and Slugs to defeat the stage's main enemy. Their stats are based on the player's Commander Level. Every stage has three optional objectives to clear. Achieving all three objectives unlocks the "Complete Now" button which allows the player to win without fighting.
- Win a battle with X ally casualties or less.
- Win a battle within X seconds.
- Kill X amount of enemies through cumulative battles.
Winning a battle earns 10 Unit Pieces of the dungeon's unit. A stage can be fought five times before it closes for a day. More unit-specific dungeon stages are unlocked by reaching a specific Commander Level.
Search & Rescue[]
The player selects a number of Unit Pieces they seek to acquire after a certain amount of time passes or by using an Instant Completion Ticket. There are three locations where the player slots units to search. The player earns pieces for one unit selected at random per location, and the number of unit pieces depends on the time set on that specific location.
- Desert City: 5 Units
- Urban District: 4 Units
- Mutant Laboratory: 3 Units
| Time | Unit Pieces |
|---|---|
| 02:00 | 8
|
| 04:00 | 16
|
| 06:00 | 24
|
| 08:00 | 32
|
| 10:00 | 40
|
| 12:00 | 50
|
After a unit reaches Grade 10, any excess Unit Pieces can be traded for Souls at a rate of 5:1. Souls can be used at the Exchange Station found in the main menu for purchasing Unit Pieces, Artifact Fragments, and EX Slug Boxes.
Abilities and Enhancement[]
Unit Layout
Units have three types of abilities: Level Buff, Possession Bonus, and Skills.
Level Buffs are unit's individual abilities and team boosts that are activated upon reaching level milestones and the unit is part of the active deployment team. The number of skills stops after Lv. 800, and the player can increase the number of ability level milestones by enhancing Units. To enhance a Unit, the player needs Unit Pieces from a number of Units and Gems. An enhanced Unit has a +[number] on the upper right of their icon per enhancement level.
| Lv. | No. of Units | Unit Pieces Each | Gems |
|---|---|---|---|
| +1 | 2 | 5
|
300 
|
| +2 | 2 | 10
|
400
|
| +3 | 3 | 20
|
500
|
| +4 | 3 | 40
|
700
|
| +5 | 4 | 80
|
1000
|
| +6 | 4 | 120
|
1500
|
| +7 | 4 | 200
|
2000
|
| +8 | 5 | 300
|
3000
|
| +9 | 5 | 500
|
4000
|
| +10 | 5 | 1000
|
5000
|
Skills are the unit's various abilities in battle or in the background. These are split into four sub-groups:
- Possession Bonus skills activate regardless if they're deployed or not. Even when deployed, some skills only activate when the unit is present on the battlefield. Possession Bonus abilities are usually related outside of the battle such as skipping stages, raising medal rewards, speeding up battle movement, and increasing Type Mastery Enhancement level. Specific units also boost Gold Mine rewards, increase Warp Energy, increase limit sizes, etc.
- Team Buffs are abilities and boosts that are given to all ally units or those part of a faction. This also includes two battle advancement abilities: Stimpack (increases battle speed) and skipping stages. Each unit has three team buffs that are individually unlocked by reaching a certain grade.
- Battle Skills are individual skills aside from stat boosts. This grants secondary effects to attacks against enemies such as freezing, poison, stun, slow movement, etc. Some units can also jump over obstacles, charge into the action quickly, or teleport at few spaces from the player's base.
- Soldier Buffs are individual timed buffs activated when deployed, after certain time passes, or when the unit is under specific HP. Each unit also has at least one complete immunity to an attack effect.
Limit Stage[]
A deployed unit and its Slug contribute to the player's Limit Stage. The Limit Stage is the highest stage the player can theoretically reach without hassle. It is counted by the combined total of the unit's level, its Type Mastery level, its enhanced level, its Slug level, and its Slug enhance level with variance from the grades of the unit and the player's War Books. For example:
 |
4,910+10+19,200=
24,120 |
 |
1722+9=
1731 |
| Limit Stage | 25,851 |
Unit Mastery[]
Once a unit reaches ★5, the player can pay 500 
Honor Coins to open up the Unit Mastery. These are skill trees, called Masteries, that go upwards in strength from left to right. The Unit Mastery uses Mastery Points as currency and are gained through the Power Defense in the Battles submode.
Each unit has three types of Masteries (Attack, Defense, and Utility) that have a number of boosts for the player to unlock and upgrade. Some boosts are relegated for use on either the Stage Battle, PVP & Alliance War, and World Boss & Alliance Raid Battle modes. The leftmost boosts are unlocked by using Mastery Points. Boosts after the first column are available to unlock once a number of Mastery Points have been used at the relative Mastery and/or the previous boost in the path has been upgraded a number of times. All units have the same Mastery layouts.
Unlocks and boosts are permanent and contribute to a unit's maximum Mastery Point amount that is shared among all three Masteries. A complete reset costs 300 Gems, and every used Mastery Point is returned to the player.
A unit's maximum Mastery Point amount is based on their grade and enhancement level. Note that each individual grade and enhancement level is cumulative with the maximum amount being 350 Mastery Points.
| Unit Grade | Points | Enhancement | Points |
|---|---|---|---|
|
|
10 | +1 | 10 |
|
|
11 | +2 | 11 |
|
|
12 | +3 | 12 |
|
|
13 | +4 | 13 |
|
|
14 | +5 | 15 |
|
|
16 | +6 | 17 |
|
|
18 | +7 | 19 |
|
|
20 | +8 | 23 |
|
|
23 | +9 | 28 |
|
|
28 | +10 | 37 |
Gear[]
Gear Layout
Units can further improve their stats by equipping seven sets of gear: Head, Chest, Legs, Hands, Feet, Weapons, and Special Weapons. Currently, only the first two are available. Gear slots are unlocked when each unit hits the respective requirements:
- Head: Reach ★8
- Chest: Reach ★10
Most Gear collected starts out in the Normal class with one Option (stat) and a level limit of 100. Gear can improve to the next class (Advanced, Rare, Epic, and Legendary) by Synthesizing with copies of the same class. Higher classes increases the number of Options and the level limit. Each type of gear has two Fixed Options that are permanent and two Variance Options that can be randomly changed by Synthesis or using a 
Switch Option Ticket. If the Variance Option is changed by a ticket, the player can revert back by paying 50 Honor Coins. Gear is leveled up by using 
Carbon.
Both Gear and Carbon are earned through the Armory Invasion by the Battles submode.
| Class | Options | Level Limit |
|---|---|---|
| Normal | 1 Fixed Option | 100 |
| Advanced | 2 Fixed Options | 200 |
| Rare | 2 Fixed Options
1 Variance Option |
400 |
| Epic | 2 Fixed Options
1 Variance Option |
600 |
| Legendary | 2 Fixed Options
2 Variance Options |
??? |
There are three types of gear:
- Common: Anyone can equip this type of gear.
- Force: Anyone can equip this type of gear, but it gives out bonuses if equipped by a unit of the gear's force.
- Signature: Only the specified unit can equip this type of gear.
| Gear | Name | Type | Fixed Options |
|---|---|---|---|
|
M27 | Common |
|
|
Desert Bulletproof Helmet | Common |
|
|
Tactical-OPS Helmet | Regular Army |
|
|
Commander Cap | Rebel Army |
|
|
Adamantium Helmet | Another Force |
|
| Gear | Name | Type | Fixed Options |
|---|---|---|---|
|
Old Jacket | Common |
|
|
New Desert Suit | Common |
|
|
Special Bulletproof Suit | Regular Army |
|
|
M36 Tunic | Rebel Army |
|
|
Adamantium Chestplate | Another Force |
|
Forces[]
Units are categorized into three forces:
- Regular Army: Immune to knockback.
- Rebel Army: Includes those from the Ptolemaic Army and Amadeus Syndicate. Immune to shock.
- Another Force: Consists of Martians, Invaders, Mutants, and independents. Immune to stun.
Faction efficiency is as follows: Regular > Rebel > Another > Regular.
Each unit has their own elemental type: Physical, Flame, and Lightning. The color shield a unit deploys with receives immunity for said type color.
Regular Army[]
Immune to knockback. These units gain an advantage against the Rebel Army, but are weak against Another Force units.
Rebel Army[]
Immune to shock. These units gain an advantage against Another Force units, but are weak against the Regular Army.
Another Force[]
Immune to stun. These units gain an advantage against Regular Army units, but are weak against the Rebel Army.
