Null

Null (ヌール) is a virus from the Mega Man Battle Network series. It moves around slowly on its side of the battlefield. However, when it goes to attack, the virus will appear in front of its target to punch. It heals itself over time and can change two panels on the target's side to whirlpools, each causing 200 damage. If the target is behind an obstacle, the virus can push the obstacle into the target, damaging the target.

Null
Nulls are blue with white eyes.

Void
Voids are purple with green eyes.

Null&Void
Null&Voids are black with red eyes.

Battle Chips
Whirlpool (ウズシオ) and Blackhole (ブラックホール) are the Battle Chips from the Null family.