Utilizing Alchemical poisons, we benefit from Legacy of Karth to keep outgoing DoTs with our Rapid Rot passive from the Necromancer tree. Utilizing a double DoT poison we can craft (Nightshade + Fleshfly + Nirnroot), Legacy of Karth will add a third DoT on top of everything. We apply this with our Dual Daggers in our front bar.

Throwing in the Phylactery's Grasp group lets us add ANOTHER DoT, making that four different DoTs applied to our target just from basic attacks (with a crit here), not including any other skills we may have. Thus, adding in our Blastbones reduces healing received. We have bouncing daggers to teleport to our enemies to close distance as well as our bow which can add another two sets of DoTs to our targets. Utilizing something of a Hindering/Debiliating posion on our bow can be useful. If they try to run, we have the bonus of Caustic Arrow allowing our Poison Injection to gravely hurt them faster, and lets us pick them off as they run.

All in all, Maarselok adds more damage into the build and fits thematically. It's based around Poison & Disease damage, mostly accomplished by damage over time. There is little escapism in here, and your downfall is if enemies tag-team you.