I have some doubts on how to rephrase a few sentences on Dr. Jekyll and Mr Hyde. I hope you can have a look at them.

1)The story is told from the point of view of Mr. Utterson, a London lawyer and friend to the brilliant scientist Dr Henry Jekyll.
2) After relating a disturbing tale of an angry fiend assaulting a small girl, Utterson begins to question the odd behavior of his friend. (I need to rephrase this: after reporting a tale concerning a fanatic assaulting a girl?).
3) Actually, his friend has created a potion capable to release his evil side, Mr. Hyde.
4) Once Hyde is released, he achieves domination over the Jekyll aspect (I need to rephrase it: He has a complete hold over him?) so that the individual is left in front of two choices. (is given only two choices?).
5) On the one hand, the man may choose a life of crime and depravity, or, on the other hand, the Jekyll aspect must eliminate Hyde by killing him. He eventually opts (??) for the second choice.

1) The story is told from the point of view of Mr. Utterson, a London lawyer and friend to the brilliant scientist, Dr Henry Jekyll. OK

2) After relating a disturbing tale of an angry fiend assaulting a small girl, Utterson begins to question the odd behavior of his friend. (I need to rephrase this: after reporting a tale concerning a fanatic assaulting a girl?). Your paraphrase is fine.

3) Actually, his friend has created a potion capable to release his evil side, Mr. Hyde. OK

4) Once Hyde is released, he achieves domination over the Jekyll aspect (I need to rephrase it: He has a complete hold over him?) so that the individual is left in front of two choices. (is given only two choices?).
Does the original that you need to rephrase include "domination" or "complete hold"?

5) On one hand, the man may choose a life of crime and depravity, or, on the other hand, the Jekyll aspect must eliminate Hyde by killing him. He eventually opts for the second choice.
Well done.

1) The perspective of the story is from Mr. Utterson, a lawyer from London who is also a close friend of the brilliant scientist Dr. Henry Jekyll. (Rephrased: The story is narrated by Mr. Utterson, a lawyer based in London, who is also a close friend of the brilliant scientist, Dr. Henry Jekyll.)

2) After hearing a disturbing account of an enraged monster attacking a young girl, Utterson begins to question his friend's peculiar behavior. (Rephrased: Upon hearing a troubling story of a furious beast assaulting a young girl, Utterson starts to doubt the strange actions of his friend.)

3) In fact, his friend has developed a potion that has the ability to unleash his wicked alter ego, Mr. Hyde. (Rephrased: In actuality, his friend has created a potion with the power to release his malevolent side, known as Mr. Hyde.)

4) Once Hyde is set free, he gains complete control over the Jekyll persona, leaving the individual with only two options. (Rephrased: Once Hyde is unleashed, he takes complete hold over Jekyll's identity, leaving the person with just two choices.)

5) On one hand, the person can choose a life of crime and immorality, while on the other hand, the Jekyll side must eradicate Hyde by killing him. Eventually, the person decides on the second option. (Rephrased: On one hand, the individual may opt for a life of wrongdoing and corruption, whereas on the other hand, the Jekyll aspect must eliminate Hyde by resorting to murder. Eventually, the person selects the latter choice.)