1) An admonisher 
[Jesuits] In the Society of Jesus, an Admonitor is an advisor to the Superior General whose responsibility it is to warn (or admonish) the General honestly and confidentially about `what in him he thinks would be for the greater service and glory of God` [Const. N°770]. That means in any matter, whether in regard to his own person (health,...
• (n.) Admonisher; monitor.
Ad·mon'i·tor noun [ Latin ] Admonisher; monitor. « Conscience is at most times a very faithful and prudent admonitor . Shenstone. » 
an admonisher.