From above link,the sentence "Those conquer who believe they can" is strange for me. The relative pronoun "who" is used after the verb "conquer". As far as I know, the relative pronoun is placed after its noun or pronoun.What kind of writing strategies is it?
"Those conquer who believe they can" is grammatical, although not especially easy to understand at first glance.
Relative clauses can be postponed and placed after the main verb phrase (see George Walkden's answer on ELU to When is it correct to postpone an attributive clause?). It means the same as "Those who believe they can conquer, conquer".