The hooded man returned three days ago on CW for the seventh episode of season three of the [Arrow](series:720988).
The hunt of this archer called Cupid, deeply affected the relationship between Oliver Queen and Felicity Smoak, during the confrontation between Green Arrow and Cupid.
We all know that Oliver loves Felicity, this is shown many times in the previous season. When Count Vertigo captured the IT specialist in Queen Consolidated. Oliver broke his promise to Tommy not to kill again. But the sweet affection that Oliver and Felicity have, was to powerful to maintain that rule. Thus killing Count Vertigo.
Another example for true affection was in the season finale, when taking down Slade Wilson(a.k.a Deathstroke). Oliver used Felicity to blind Deathstroke. This truly worked eventually. But the aftermath caused the Oliver to make his move on the IT Specialist.
Dinner didn't go well of course when the REAL Count Vertigo fired a rocket launcher in the restaurant. This started cutting the glue that was connected with Oliver and Felicity.
Then came Ray Palmer(a.k.a Captain Atom), owner of Palmer Technologies. Mr. Palmer was basically a hotel to Felicity. He gave here a good job, high paying salary, expensive French dress, and let Felicity take days off.
Ray Palmer doesn't want Felicity but he using her as a distraction.
So Ray Palmer actually wants to use Oliver Queen's company to make Advanced Weaponry, and an exquisite exo-skeleton suit. Thus revealing he is Captain Atom.
So he basically Lex Luthor, only he's good-looking and not bald.
This drives Oliver a bit off the edge. So he goes to a place where he can calm down from his anger.
We'll find out where he went in the next episode.