An Anti-Ethernano Tumor (アンチエーテルナノ腫瘍 Anchi Etērunano Shuyō) is a malignant mass a Mage can develop through constant overexertion of their Magic Power.
Description[]
An Anti-Ethernano Tumor develops over time, after years of consistent Magic abuse; the symptoms appear to be acute despite the time required for the mass to develop to a detrimental size. Said symptoms appear to be deadly, as very shortly after the tumor had festered long enough inside its victim, Natsu Dragneel,[1] he fell comatose and his heartbeat could no longer be heard. The only known way to remove the tumor is via immediate surgery, however, it has been said that no surgeon in Ishgar has the required skill, and even Magic the likes of Sky Dragon Slayer Magic and Sky God Slayer Magic are ineffective at mitigating the malign effects the tumor causes. However, a Magic that manipulates mass can be used to shrink the tumor to a size so miniscule that it would render it benign.[2]
Etherious-based energies implanted inside a human can be mistaken for an Anti-Ethernano Tumor.[3]