UMP40/Strategy

As a T-Doll UMP40 is very unique and belongs in a very specific niche, both her individual performance and formation effects suggests this.

Individual Performance

Skill

UMP40's one-of-a-kind skill defines her unique properties, her active skill is a permanent toggle skill with a cool down of 666 seconds, it is unlikely for any combat sessions to last over 11 minutes for it to be available for activation again.

Leaving the skill inactive UMP40's evasion rating will increase every two seconds while lowering her damage, this effect stacks five times. Activating the skill will remove all the current buff and debuff stacks on UMP40, after activation her own damage will increase every two seconds while lowering her own evasion, this also stacks five times. At level 100 with no equipment, having her skill be inactive will raise her evasion to a value of 121 and lower her damage to 21 after 10 seconds, activating the skill will boost her damage to around 71 (70.5) while lowering her evasion to 18 after 10 seconds.

The graph below shows stats change with skill activation, green represents a lv100 UMP40 at the beginning of the combat session, cyan shows maximum stats when Overload is inactive, orange shows maximum stats after achieving maximum Overload stacks:

Stats

UMP40's stats are similar to the other two UMP T-Dolls in the game, she is somewhat in the middle ground of ^SMG UMP9UMP9UMP9 and ^SMG UMP45UMP45UMP45. Provided with the same equipment, 40's combat performances should be somewhat similar to the other two UMPs, if the unit skills are not taken into consideration.

By default, UMP40 has very average stats, she sits comfortably on the average line when drawn on a chart as visualised below, green represents UMP40 while red represents SMG average:

The graph below shows the growth curve of UMP40, yellow indicates UMP40 at level 1, green indicates UMP40 at level 100, purple shows UMP40 with maximum possible values, day combat optimised and exclusive equipment, Oath certificate, max affinity:

Combat Performance

As a DPS unit

UMP40 might just be the highest DPS output SMG unit, or even out of all the dolls in the game, simply because she can achieve permanent empowered uptime.

Entering combat and having the skill activated, UMP40's own damage stat increases to a staggeringly high value after 10 seconds, with the 271% permanent damage increase empowered uptime she can literally contest the MVP title against all the dolls in the game. To put into perspective, the other popular damage purpose SMGs in the game are ^SMG SR-3MPSR-3MPSR-3MP, but SR-3's skill is a toggled based and it leaves her with a total of 62.5% total up time, and it only adds 260% extra damage. Doll ^SMG C-MSC-MSC-MS is also capable of permanent empowered uptime, but her damage bonus is only 85% at max level.

Permanent uptime is crucial in dealing damage during in extended combat sessions such as fights against bosses. In fact her 271% damage increase completely negates the armour piercing penalty induced by the HP ammo. By the event of Deep Dive, the event bosses are actually starting to appear with armor values, some of the low damage per shot type AR dolls are starting to struggle, where as 40 and her 271% damage increase just completely overpowers the armour value and continues to smash large damage values.

But the draw back of the skill is an evasion rating penalty, for every stack of damage up she gets, UMP40 loses 25% evasion. She will become an easy target for the enemy units because at max damage stacks, she will also be penalized for -76% evasion, especially when she is placed on the front line of a typical echelon formation. Some bosses would prioritize dolls positioned in slot 8 over those at slot 5, players may have to move the slot 5 doll forward to draw the aggression.

As an Evasion tank unit

UMP40 can function as an evasion tank, though it is considered less optimal due to her innate low HP pool and being unable to boost AR units.

By leaving the skill inactive UMP40's evasion status also increases up to a maximum value of 61% permanent increase, in theory this will allow her to perform somewhat similar to what ^SMG C-MSC-MSC-MS would, but to achieve this 50% UMP40 needs 10 seconds, where as C-MS can achieve 65% under 2 seconds. Choosing to leave the skill inactive will also give UMP40 a damage penalty, with every evasion stack gained, she loses 5% damage, upto a total of -23% damage loss.

Similar to ^SMG C-MSC-MSC-MS, UMP40's relatively low HP pool does hinder her tanking performance, this means she isn't as good as the other top tier SMG evasion tanks such as ^SMG RO635RO635RO635 and ^SMG MP7MP7MP7, despite the latter listed two being burst evasion bonuses.

Formation

Tile Bonus

40's tile buff and shape are also considered unique amongst SMGs, she provides 500% critical rate increase for other SMG units in the tile 8, 9, 2 and 3.

Affects Submachine guns

Increases critical chance by 500%

Large magnitude...?

Many players would have been amazed upon seeing the 500% increased crit rate, it may seem like a big value, but SMG units by default only have 5% crit rate, when increased by 500% it only adds up to 30%. Since that equipment added stats are calculated before tile bonuses, 100% crit rate on a SMG can actually be achieved by fitting a suppressor, however that will take up the accessory slot, meaning the SMG unit can no longer mount optics and lose out on accuracy. Fitting a telescopic scope is not advised as it over shoots the crit chance stats by a large margin, any further bonus after a doll reaches 100% crit rate is considered wasted.

Limited benefactor

UMP40's tile bonus are provided to SMG units, which is unusual since she is a SMG herself. Her inability to buff AR units on her tile dissuades her usage as a main tank, since being unable to provide buffs to AR dolls can be considered a major weakness in AR/SMG formations, the vital position of tile 5 is usually occupied by dolls such as ^SMG G36CG36CG36C or ^SMG C-MSC-MSC-MS with their powerful tiles that effects all three AR dolls on the back line.

For example ^SMG RO635RO635RO635's large coverage tile, with this she sits comfortably in the central position 5 of any (or most) AR/SMG formations.

The typical 7, 4, 1 coverage tile found on many main tank SMG dolls.

To an extent being unable to buff AR dolls dissuades her usage as a T-Doll, powerful as UMP40's individual damage output is, having her in an echelon would mean less tile bonuses for ARs. A 500% crit rate bonus to the main tank SMG in a standard AR/SMG formation contributes very little to the echelon.

Compatibility

As a DPS unit

As opposed to some other DPS based SMG units, when one uses UMP40 as a DPS unit she benefits from three stats, Accuracy, Damage and Rate of fire.

By default SMGs lack the accuracy rating to effectively hit every single shot they shoot, any AR dolls who can provide accuracy bonus would be superb back ups for UMP40.
UMP40 is able to reach a relatively high constant damage rating with her skill Overload, any further bonuses to her base damage stat will boost her damage per hit exponentially.
Average SMG rate of fire actually has room for improvement, UMP40 can manage a 85 cyclic rate of fire, this means she can benefit from up to 41% rate of fire increase tile bonuses without hitting the 120 game built in rate of fire cap.
- Or up to 48% if UMP40 is equipped with a fully enhanced 5* Holographic sight.
List of some AR dolls with beneficial tile bonuses for UMP40: ^AR AK-15AK-15AK-15 (Primarily damage, large accuracy), ^AR AK-12AK-12AK-12 (Primarily damage, some RoF), ^AR K2K2K2 (Primarily damage, some accuracy), ^AR G11G11G11 (Large damage, some evasion), ^AR ACRACRACR (Primarily accuracy, large RoF increase).
^AR MDRMDRMDR and ^AR Howa Type 64Howa Type 64Howa Type 64 can actually shield friendly SMG dolls while providing hefty damage tile bonus, having them in a formation with UMP40 can improve both her survival chance and damage output.
- Modified ^AR G36G36G36 skill 2 adds a passive, she can increase evasion for dolls standing on her tiles at the time of her own skill activation. ^AR G36G36G36 also provides one of the strongest offensive oriented tile bonus for SMGs, up to 30% damage and 15% (10% non-modified) rate of fire increase.

Having UMP40 as a DPS SMG in an ARSMG echelon places stress on two factors, the total amount of available tile buffs, and the main tanking slot 5 doll.

Using UMP45 as the slot 5 doll can partially negate the lack of buffs, because UMP45's tile bonuses are actually considered really strong for her rarity. As of Continuum Turbulence, UMP45 received digi-mind modification, improving overall doll performance.
Using ^AR M4A1M4A1M4A1 or ^AR AUGAUGAUG in the centre of the echelon can cover some of the loss tile buffs.
Players can also make use of HG dolls who can provide attribute increasing active skills, as well as strong tile bonuses.
Using tenacious slot 5 dolls such as ^SMG C-MSC-MSC-MS and ^SMG P90P90P90 is also advised, since they can hold back the entire enemy formation on their own (most of the times). It is worth mentioning ^SMG P90P90P90's skill holograms can actually draw fire away from enemies, covering UMP40 in slot 8.

As an Evasion tank unit

Give her evasion boosting tiles, some possible candidates as following: ^AR G41G41G41, ^AR AN-94AN-94AN-94, ^AR TAR-21TAR-21TAR-21

As one of the few dolls with added crit damage multiplier from exclusive equipment, a few selected fairies can be selected for UMP40's echelon to amplify this effect further:

Fury Fairy - large crit damage multiplier bonus, critical chance active skill, but no damage bonus
Command Fairy - large crit damage multiplier and damage bonus
Parachute - large crit damage multiplier and damage bonus (can be extremely difficult to obtain and almost a nightmare to enhance)
Yae Sakura - crit damage multiplier and damage bonus (can be difficult to obtain and difficult to enhance)

Some fairies provide alternative bonuses also suitable for ARSMG type echelons, as following:

Shield Fairy - largest evasion bonus, fairly high accuracy bonus, as well as SMG shielding active skill
Rescue Fairy - largeest crit accuracy bonus, fairly large evasion bonus
Chloe - Fairly large evasion bonus and decent accuracy bonus, damage absorbing hologram active skill (can be difficult to obtain and difficult to enhance)

Equipment

Slot 1

UMP UX Exoskeleton	A piece of equipment available and exclusive to all UMP dolls, this particular Exoskeleton provides the unrivaled +35 evasion bonus of a T4 exo-skele while having no active damage penalty, instead it offers a little bonus in critical damage. Having this exo-skele can provide the maximum evasion bonus for UMP40 without hindering her damage output potential, a fine addition for the T-doll.
IOP X4 Exoskeleton	X series Exo-skele does not have any damage penalties, one can make use of this if they do not have the exclusive equipment but wish to use UMP40 as a DPS SMG.
IOP T4 Exoskeleton	T series Exo-skele boosts the maximum evasion rating while having damage penalties, one can make use of this if they do not have the exclusive equipment but want to utilize UMP40 as a tanking SMG.

Slot 2

ILM Hollow Point Ammo

(Most) SMG units can only equip HP ammunition as their slot 2 equipment, upgrading this equipment will boost UMP40's damage exponentially. However if one chooses to have UMP40 as a tanking SMG unit, one can neglect this equipment slot and give the high grade HP ammunition to other damage dealing SMG dolls.

Slot 3

EOT 518	Holographic optic provides both damage and accuracy, the two stats that are vital for a DPS type SMG. The rate of fire penalty is rather negligible on a SMG doll, since most SMG dolls by default have above 85 innate rate of fire and the fact that many AR dolls are able to provide rate of fire bonus on their tiles. With this optic installed, UMP40's damage output will increase significantly.
PEQ-16A	When used as a DPS unit, night combat equipment is recommended on UMP40 for night sorties.
AC4 Suppressor	One can make use of a suppressor if they are using 40 as a tanking unit, as it provides additional evasion.