DigiCore

From DigimonWiki

A DigiCore is a very powerful source, with each Digimon possessing one. The exceptions are the Digimon Sovereigns, Ebonwumon, Baihumon, Zhuqiaomon, and Azulongmon, and their master Fanglongmon. Each of these Digimon posses 12, which surrounds their bodies, usually in a ring formation. The Digicores have amazing power, in Digimon Adventure 02, Azulongmon gave Gennai one of his, which in turn allowed for Paildramon to become Imperialdramon for the first time. It also gave the original DigiDestined's Digimon the power to digivolve to their Ultimate level once again. Another one of Azulongmon's also allowed Agumon to digivolve to WarGreymon.Also, if one of the DigiCores are gone from one of the Digimon Sovereigns then the Digital World's defenses will weaken making the Digital World unbalanced.