Within the context of the Bhagavad Gita, who or what controls the intellect/mind/senses?

E.g.
yas tv indriyani manasa
niyamyarabhate ’rjuna
karmendriyaih karma-yogam
asaktah sa visisyate

One who controls the senses by a trained and purified mind
and intellect and engages the organs of action to selfless
service, is superior, O Arjuna. (3.07)