Assuming you mean Rector Drath, fast, with good HP/DEF. If you can afford to, accuracy to land the A1 and resist (depending on the content) never hurts. 

Yes  thats  what  i  meant  and  thank  you  

aim for over 200 spd

aim for 200 acc if you need the atk down

aim for 300-350 res 

aim for 60-80k hp

aim for 3-4k def

sets can be any you have the mentioned stats for, any set with special effects are nice to add, some of which can be relentless/immortal/regen etc 

kind regards