This article's content is accurate to the most recent public game version, 0.4.8d.
Ailment Defence is a positive status effect which increases the resistance to all common negative status effects for four turns, at a 50% reduction. However, it has no impact on other debuffs such as STAT Down. It is a weaker version of the 
Ailment Guard status effect. Also, having this status effect lures certain opponents into using Shatter Magic, a spell which negates all positive status effects, including this.
Player Sources of Ailment Defence
Monster Sources of Ailment Defence
- None