هٰذَا الَّذِي تَرَكَ الْأَوْهَامَ حَائِرَةً
This is the person who left minds bewildered.
A demonstrative makes an object identifiable through pointing, whether literal or mentally represented. Forms such as “this” and “that” can identify what the hearer is directed to attend to.
Beyond identification, a demonstrative can focus attention and make the referent vividly present. Its additional rhetorical effect depends on what is said about the pointed-at person or thing.