Stephen Amell as Oliver Queen and Emily Bett Rickards as Felicity Smoak in The CW supernatural series 'Arrow'.Facebook/Arrow

"Arrow" will be back on The CW with Season 3 episode 21, titled "Al Sah him", this Wednesday, 29 April, at 8 pm, and is likely to focus on the darker side of Oliver Queen (Stephen Amell).

The official synopsis of the upcoming sequel states that the protagonist will go through a rigorous transformation. So, it can be assumed that he is planning to accept Ra's al Ghul's (Matthew Nable) offer and become the leader of Assassins.

The trailer of supernatural series hints at the transformation of Amell's character into the powerful leader of evil kingdom as he is seen urging the villains to address him as Al Sah-him, heir to the demon.

But fans of The CW series believe that their superhero can never turn himself into a villain and his decision to replace Nable's character is part of a master plan, according to Melty.

Meanwhile, the description indicates that Nyssa (Katrina Law) could be in danger while training Laurel (Katie Cassidy) as the League of Assassins will set their site on her. Although Law's character will decide to fight back her enemies, Cassidy's character will seek Felicity Smoak (Emily Bett Rickards) and John Diggle's (David Ramsey) help.

On the other hand, several spoilers have teased that Thea Queen (Willa Holland) might turn evil after her resurrection since the powers of Lazarus Pit is likely to have some psychological affects on her.

However, it remains to be seen where the storyline of "Arrow" will take its viewers by the end of episode 21, titled "Al Sah him", which is said to be one of the most thrilling sequels of The CW series.