For the most part things are going to be pretty straight forward for the Tortage phase of the game (up to level 20ish). It seems they did a bit more tuning with some of the quests so they're not quite so difficult as they were in previous incarnations, which is nice
The most mobs the Demonologist should encounter at once at the lower levels will be 2, so it's fairly simple to cast Storm Chains to root one and then DD the second down. Keep in mind that the demon is going to attack the first mob you cast a hostile spell on if you have it set to 'assist', so it can increase the chance of Storm Chains breaking early, though for the most part it holds fairly well in PvE when you use it on even-con non-boss mobs
The other thing to keep in mind with Storm Chains is that your target can't turn around while rooted. This is of particular use vs. casters or ranged attackers so long as you're somewhere behind / to the side of their attack or casting cone when your root hits
Otherwise it's not a bad idea to get used to how dodging and active blocking work at the lower levels
The Demonologist can dodge in basically any movement direction by double tapping the directional key as long as you're in 'combat' stance. Dodging backwards in particular is a good thing to get used to doing since it can cause melee swings to miss and gives you a few second 'Evade' buff. You'll really start to notice a difference later on since combos will take 3+ swings to execute, so a well timed dodge will cause the combo to fail
Health potions are a good thing to keep on your hotbar as well. I rarely needed them at earlier levels, but once you get Pact with Set at level 20 the heal over time effect will basically counter the self-damaging component of PwS. The spell is still somewhat situational, but it works wonders vs. boss mobs to help burn them down quickly. If you plan on doing any PvP at all, the health potions are a must either way since we are indeed quite squishy, even with a lot of feat points dumped into the general Mage tree
At lower levels, the Demonologist will be good to go in terms of survivability in PvE without a single point spent in the general Mage feat tree. From my experience though, that changes dramatically once you hit the mid 30s or so. It's honestly like a night / day difference between investing in the general tree or not, which gets even more apparent if you plan on dong any PvP at all
That eases off a bit again later on since we'll have more CC options available, more points to invest in Havoc or Conflag. (increasing overall dps) and then Spellweaving which can give us a nice +dps boost (which, combined with Pact with Set will see our dps hit some impressive numbers). Basically at that point we can burn targets down much more quickly, so we don't need quite as much defense since fights shouldn't last nearly as long as they will at mid-level ranges
- Always keep a heal potion ready.
- Make sure you're fully armored/clothed. (I know we all want to see those M rated body parts, but we're talking about surviving here!)
- Have all of your buffs active (especially Protection of Set).
- Make smart use of your root.
- If you're getting swarmed and you have room, just run! Guys will stop following you after a few seconds.
- If you root one guy and run right away, the guys that chase you (BAFs) immediately will eventually drop off, leaving only the rooted enemy for you to fight. I used this tactic numerous times when there were 4-5 mobs clustered