OK, I just thought of this and am not sure if it falls into the improper timing cattegory which has been discussed lately.

Opponent plays Duo. Random pick is either Despair from the dark or Night Assailant. Then another chosen card is picked and is Sinister. Will the first monster discarded get it's effect or is it improper timing since it wasn't the last thing to happen in the chain?

In this case, "Despair from the Dark" or "Night Assailant" won't miss the timing. Their effects resolve in a new chain, after "Delinquent Duo" has resolved.

Fear/Despair from the Dark's and Night Assailant's effect will take place after Delinquent Duo has fully resolved, I believe. So after Sinister is discarded, Despair from the Dark's or Night Assailant's effect will activate. I think that's how it'd work

So what causes improper timing? I read something a while back about DMOC not getting a spell card if timing was off on the chain and it not being the last thing to happen and thought this might also fit.

Yeah, DMoC's Magic retrieval effect takes place as soon as it's summoned, but if it's special summoned in the middle of a chain, it doesn't work because you can't "interrupt" a current chain to start a new one.

Another mistiming accures after petten the dark clown is discarded but the chain is still resoving.

~ Davis

Please read the Frequently Asked Questions Sticky before posting. I posted somthing that Covered Timing issues.

http://yugiohrealms.com/forum/showthread.php?t=415811

This is the post that Covers Missing the Timing - Optional Trigger Effects:
http://yugiohrealms.com/forum/showpo...6&postcount=11

Just to clarify. In this situation, both the cards are considered to be discarded together at the same time.