My DM and I are trying to port a Drow Night Stalker Assassin, as released on Dragon magazine 379, from 4e to 5e, but we're having some troubles. As we see it, using the Pact of Blade Warlock as bases is a nice starting point. We have figured the shadow step, on lvl 6 I'll get shadow monk's shadow step instead of warlock's Patron feature. But our main problem is the shroud ability. AS we see, the rogue sneak attack is the nearest feature we can adapt from. Actually this part shouldn't be a big problem. My main concern is, what should I take out from warlock to get sbeak attack / shrould? My DM sugested to get half of the sneak attack damage per level for half of the spellcasting from warlock (ie. spell known, spell slots, slot level). Other option would be get all sneak attack damage for all spellcasting ability.
What do you think? is it a fair trade? Do you have any other suggestions? Thanks in advance