Good level to do the DLC at?

well depending on what you acquired there is many questions to be had mostly the armor is only good up till like level 10ish then it's best just to have armor you can buy but the weapons could carry you further specifically Mortis and the Gauntlets of Salvagry from the dlc that gives the quest with Karn are 2 expecptional dlc weapons because Mortis does a TON of hits which the damage then adds up quick (I still use it even at level 20) because of the quick hits it can also be good when combined with the grim talisman for quick reaper energy gaining, now mortis isn't really that great against BIG foes unless your over level'd or have awesome stat armor, in this case you'd want to use the Gauntlets of Salvagry because of one thing -25% reaper energy cost this allows you to use a great deal of Death's skills especially when combined with a full set of equipment that lowers cost further I was level 12ish and I had up to -50% off reaper skills

now finally I'm not sure if you got this yet or not but if you can get your hands on the crow armor set as well you should do so not because of the armor because again it's only so good and fails in comparison to what you can buy but the weapon pretty much makes you a god on it's own and it's only lvl 15

what the Crow Scyth's do is so special is Health and Wrath Steal of 9% each now this might not seem like much but trust me if you combine it with a good set of equipment you can pretty much completely fill your wrath in only a couple of swings also it has a hidden ability which when you cause a execution it'll completely refill both your health and wrath

as far as the possessed weapons are considered I think it's just there for early possessed weapons which is kind of pointless since you can't get the good stuff till later and it's a lot of time and money to build and you can only level them up once so if you screw up then you'll have to start over

understand that everything is based on opinions so it's up to you weather you find them to have the same value as me but I personally find these 3 weapons are probably the best weapons in the game at least for your first play-through since I haven't tried the weapons you get from draven since it's a lvl 22 weapon just so you know that weapon is also tied with quest you get from karn to get the gauntlets

also the other 3 scythes you get offer well skills and abilities but start to lose there hold around the same level of the armor or until you can wield crow scythes

lol there is a reason why Mortis is part of the Abomination set and it's pretty much Aegis Burt which allows for a TON of flinching a TON of extra hits both small and large AND it gives this special set of Gauntlets the one thing all Gauntlets lack when compared to a heavy weapon AOE damage

just wanted to mention that just for your knowledge