It's NOT 'any time'. It's a new mechanic. 'Trigger / Conditional Specials'. Almost all new contents from now on will have trigger specials with specific conditions.
Illuyanka will buff herself with THREE (which you failed to mention) dmg cut shields on the '1st turn' and once more 'after 50% hp or less'.
aight thx
sry i don't jerk off to the wiki
selling brand new account with L/E SSR and full plus more fire team.