Hub.BAT

The Hub.BAT / Hub Batch, known as Saito.BAT / Saito Batch (サイトバッチ) in Japan, is a program from the Mega Man Battle Network series that when equipped into MegaMan's system completes Hub's DNA to be 100% like that of Lan Hikari. When MegaMan was created by Dr.Yuichiro Hikari he was the first NetNavi to have had human DNA incorporated into him to create a better bond with his NetOp Lan.

Hub was Lan's identical twin brother who died shortly after birth, meaning that they originally shared the same DNA. Yuichiro feared that if the DNA were the same in MegaMan, any damage received by MegaMan would affect Lan, and vice-versa. As a result, Hub's DNA was changed by 0.001% to prevent complete Full Synchro with Lan Hikari. (The 0.001% is presumed to be eye color, as Lan has brown eyes, but Mega Man has green eyes.) When the Hub.BAT is added to MegaMan, the 0.001% difference is removed and MegaMan's code becomes 100% in synch with Lan's DNA, enabling them to go Full Synchro.

History
In Mega Man Battle Network, MegaMan had been severely damaged by MagicMan.EXE's life magic attack and Lan's father had sent Eugene Chaud with the Hub.BAT program in hopes of boosting MegaMan's power. After revealing the truth about MegaMan's creation, Lan reboots MegaMan with the Hub.BAT and MegaMan's programming gets rewritten, strengthening his power enough to defeat the Life Virus.

While not used, the Hub.BAT program is mentioned during the events of Mega Man Network Transmission, as Lan wonders if they can defeat the reborn Life Virus without it.

In Mega Man Battle Network 2, after MegaMan defeats every V3 NetNavi with an S rank (excluding Bass), next time when he style changes after a random battle, he receives a style called HubStyle. With this style MegaMan gains the abilities of the Guts, Shield, Custom and Team Styles, maxing all stats, but halves his Max HP. (Note: This style can only be gotten once. If the style is deleted or it is not chosen upon the style change, the player can never obtain it again).

Mega Man Battle Network 3 presents Lan with the Hub.BAT as a Navi Customizer Program that "brings out MegaMan's full potential". The program gives him over 15 abilities, but causes a bug that halves his HP and always causes an error. In addition, this program needs to be modified (with ModTools) no matter what style he is in. (To counter the natural errors of this program, including the HP loss, equip the Navi Customizer Program called BugStop, which is obtained from leveling a BugStyle to Lv.2).

The Hub.BAT appears as a Giga Chip in Mega Man Battle Network 6 (Falzar version only) which works the same as the program from Mega Man Battle Network 3 without the HP glitch.

Trivia

 * MegaMan and Lan gain the ability of Full Synchro as a battle mechanic starting in Mega Man Battle Network 4, alluding to the strong bond between the duo. It was used story-wise in the end of Mega Man Battle Network 3, in the same way as the previous bosses had.
 * In computing, ".bat" stand for "batch", which is a type of file that contains a series of commands to be executed by a program. As a result, Hub.BAT is also referred to as HubBatch.