If you want to keep him condition-based, then you’d want to fill out the curses trait line. Since our trait lines have practically NO synergy with the other trait lines, you can choose which one to invest in yourself without too many problems. Curses line does help with Death-Shroud though, with one major trait allowing you to bleed and weaken an enemy near you when you go into DS. I’d advise investing in either the death magic or blood magic lines though so your necro isn’t too squishy.
Keeping with the conditionmancer build, you’d want to main a scepter and use a dagger/focus offhand. (Dagger’s more offensive with the ability to weaken, bleed, blind and shove three of your own conditons onto the enemy. Focus is more support oriented, with the ability to cast vulnerability, regenerate health and chill/de-boon an enemy). Alternatively, you could have a warhorn offhand if you want to daze someone and then get away casting swift.
Your second weapon choice is up to you. I personally would choose a staff, due to the range and the aoe attacks. Hope I helped..
