Roll chip series (BN6)

Roll3
Roll3
Description	Attacks enmy,then heals you
Full name	Roll V3
Class	Mega
Library #	3
Element	None
Attack power	60
Codes	R
MB	60 (max 1 copy)

Roll2
Roll2
Description	Attacks enmy,then heals you
Full name	Roll V2
Class	Mega
Library #	2
Element	None
Attack power	40
Codes	R
MB	40 (max 2 copies)

Roll
Roll
Description	Attacks enmy,then heals you
Full name	Roll
Class	Mega
Library #	1
Element	None
Attack power	20
Codes	R *
MB	20 (max 4 copies)

The Roll Navi chip series are Screen-dimming Mega chips that summons Roll to deal three hits of None element Flinching damage, then heals MegaMan for the amount of damage Roll dealt.

Roll deals 20 damage per hit, totalling 60 damage.
Roll2 deals 40 damage per hit, totalling 120 damage.
Roll3 deals 60 damage per hit, totalling 180 damage.

Notes

Roll can be used over broken/hole panels.
Roll cannot attack the enemy if they are on or behind the user's column.
The user is always healed for the total damage Roll would have dealt even if she was unable to attack.
AntiRecv cuts the Roll user's HP for the chip's base total damage, regardless of how the user boosts the chip's damage before using it. Example: When the player uses a Roll3 attached with Atk+30 to trigger the enemy's AntiRecv, the user's HP will still be cut by 180.
If Roll is taken by a player's AntiNavi, Roll will not trigger the other player's AntiRecv, and will proceed to attack (if able) and heal as normal.

Competitive Overview

The Roll Navi chip series exchanges a Mega Chip slot(s) for a powerful healing option. While boasting deceptively low damage on paper, Roll3's 360 HP swing at base is nothing to scoff at, and damage boosts will make Roll even more threatening.

If aiming for optimization, Roll3 is used over the two weaker versions due to competitive Mega Chip slots, and stacking damage boosts on one Roll rather than splitting boosts between two Rolls will save a Mega Chip slot.

Some common Roll3 damage/heal values to consider:

Roll3 at base deals 180 damage (will not break a fresh Barr200).
Roll3 + Atk+30 deals 90x3=270 damage.
Roll3 + a full value DblPoint deals 120x3=360 damage.
Roll3 + Atk+30 + a full value DblPoint deals 150x3=450 damage.

( Navi+20 is not mentioned due to its next to no usage in PvP)

Notice that when any of these values are doubled by gaining Full Synchro or Anger from landing Counter hits or Emotion Bug, the damage/heal values become incredibly high, and some double damage combinations even break LifeAur on the first hit.

Roll players often build their folder around Emotion Bug to take advantage of these game-deciding HP swings. Common appendages to support retaining Emotion Bug such as Shield, Reflect, AntiDmg and HubBatc (to acquire Shield and perhaps stall Custom Bug) can also help Roll players take less damage and avoid using Roll too early to gain full value from the potential healing.

Counterplay

Most traps and defenses are very effective versus Roll.

Defenses that negate/mitigate damage such as Barr200, AntiDmg reduces the HP swing value.
AntiRecv negates the damage and even cuts the user's HP instead of healing them.
AntiNavi steals Roll with all damage boosts included.

If Roll is played with Emotion Bug and the player is forced to use BugFix, they will lose the potential double damage from Roll afterwards.

Roll and damage boosting chips are usually not wanted early in the Custom Screen. While Dust Cross and Charge Cross can somewhat deal with this problem (by using Trash Chute and increasing Custom size, respectively), going into them means the user loses access to Base MegaMan's Emotion Bug, protective B+Left abilities, and their late game capabilities (e.g. Charge Cross's Charge Shot to nullify BgDthThd)

In a Damage Judge situation, Roll's heal might let the enemy deal more damage to the user, causing the player to lose the round. FstGauge can be used to accelerate the game towards this case.