Tainted is a stat boost that lowers all stats and/or rates of the character in return for no failed summons via Gaia's/Yile's Summoning.
This is a blanketed boost.
Tier I
Lowers all stats by -1 in return for a 25% of failed summons via Gaia's/Yile's Summoning instead of 33%.
Tier II
Lowers all stats by -2 and perma-stat increase rates by half in return for 10% failed summons via Gaia's/Yile's Summoning instead of 33%.
Tier III
Lowers all stats -5 and perma-stat increase rates as well as experience gained by half in return for 0% failed summons via Gaia's/Yile's Summoning.