Katsuyu: Immense Network Healing is a cooperation ninjutsu used by Katsuyu and its summoner using the link shared via the Strength of a Hundred Seal.
Firstly, Katsuyu divides its body into several smaller clones, and then each attaches itself to a person. The slug's summoner then channels their medical chakra through Katsuyu, who in turn transfers it to the wounded person, healing their wounds, restoring their stamina and chakra reserves.
This technique allows the user to heal a great number of persons simultaneously regardless of distance. While using this technique, the user is linked with Katsuyu, allowing them to communicate with the slug and sense what it encountered on the battlefield.