recently i have been using the blood magic witch active ability alot. I find it super interresting to use as its a huge power boost to your damage as well as a great challenge to use since it burns your health bar although thier are many ways to deal with that set back i find the skill overall very fun to use and it makkes the game a real challenge especially early on.
so far i have tried a magic build where i use only periodic effect attacks or summon monster spells (primarly the muumy) and life drain. the goal of the build is to get the passive impending doom (whether you get it from new game+ or train it is up to you, although i prefer to start with it in new game plus as it requires you to differ to much from a more INT bassed build). since blood magic, as opposed to stealth, grants your next skill 100% crit chance, ALL of the damage will crit so placing a lot of different poisons or periodic affects with the use of blood magic maximises the ninja passive giving you near instant cooldown affect your items should be centered completely on black candles to increae the damage of your crits and since you will be putting points in endurance for the witch abilities and for more tankiness you should use the life leech passive to keep your health from going down to fast. life drain of course is your primary source of heal, dont worry with all of the poisons doing crits you will be able to spam the hell out of life drain. other passive abilities are of course boosting your spell damage and arcane potency for more crit damage.l this build is tricky to use in arena and not really great because of your constant life lose, But its a anti boss build you can literally kill a boss in 30 secs even if you are like 4-05 lvls under the recommended level.
other interesting combinations with blood magic include using aegis/last stand/defend to prevent life lose or of course maximising your life drain as much as possible.
have any other ideas tell me all about it.