Neuro Immunodeficiency Syndrome
From Sonic Retro
Neuro Immunodeficiency Syndrome, also known by the acronym N.I.D.S., is a disease originating in the Sonic games continuity. It is best known for afflicting Maria Robotnik, as recounted in Sonic Adventure 2.
N.I.D.S. is an incurable and inevitably fatal disease. Gerald Robotnik, on being ordered by the United Federation government to research clinical immortality under Project Shadow, realised that his attachment to the Project on the Space Colony ARK could potentially yield a cure for the disease as a by-product, and thereby save his grand-daughter. Of the many agendas represented in the work of the Project, Gerald's motives to find a cure for N.I.D.S. were perhaps the purest; but all for naught, when G.U.N. stormed the facility and violently shut the research down, killing Maria in the process.
It is unknown if Shadow the Hedgehog actually does harbour the cure for N.I.D.S. or not; but with Maria fifty years dead, the point is somewhat moot.
In other media
In the Archie Sonic the Hedgehog comics, Buns Rabbot - an alternate reality version of Bunnie Rabbot - suffers from the disease. Dr. Ivo Kintobor produced a special medical suit, the Omega Care Unit, that stops the disease from progressing, but requires the sufferer to remain quarantined inside.