Board Thread:Arrow discussions/@comment-25029540-20151202190752/@comment-11526603-20160401040955

What we know right now is that Oliver and Felicity survive (although she could just be an hallucination like some are suggesting but I doubt it).

The person in the grave is close to both Oliver and Felicity, though Felicity seems mostly affected by this death as it completely shifts her morals of taking a life when she tells Oliver to "kill that son of a bitch".

Barry Allen cares enough to visit the person's grave.

The death happens in April. Since the series takes place in present time, that means that it will be revealed within the next 2-3 or it could be within the next episode like a lot of sources are saying.

I might be wrong on this but I'm placing my odds on Felicity's mom and here's why:

1) She recently returned to the show in the last episode. So now she may very well be involved in whatever mayham is about to occur leading to her death.

2) Felicity seems the most affected by it.

3) Oliver is sad but it looks like he's sad because maybe he feels guilt or effects of not taking sufficient measures to avoid this. Maybe responsible as he states that it's his responsibility.

4) Barry visits. I don't think that Barry has ever met Felicity's mom but out of all of the members in Team Arrow he is closest to Felicity. So he visits out of pure respect.

5) This didn't come from me but somebody pointed out that in episode 15, Vixen tells Oliver that in order to keep his son safe he has to keep him away from his world, and he does so by sending him to an unknown location which even he is unaware of. Officer Lance does the complete opposite, he tells Felicity's mom everything about Damien Dhark and HIVE, so she's not safe anymore.

So those are my thoughts for now.