I’d swap Gloom Leaf for Sylvanimora. It will allow you to do AOE damage and leave a skull match for the AI to take whilst entangle, so basically a free turn!
Staff of Madness*** (Necromancer)
Red is there to fill up from the explodes.
Also been using the following loop team with the Necromancer class which I traited up because of the flood of spirit stone events.
Team bonus: +2 armour, Banner of Progress
Prioritise filling Hellcat, depending on board. Aziris is cheap so will have little impact on blocking red mana. His spell is great at keeping the turn and picking off the lead troop weakened by Death Knell or Hellcat. Being able to +4 match skulls is a regular occurrence.
Death Knell packs a serious punch, doing 28 damage plus the utility of extra turn. It will generally target either the first troop or Hellcat’s first target, as they are the troops more likely to sustain damage early on.
No green or blue mana troops is fine as you will want to convert those colours to either red or yellow. Troops don’t rely on traits either to be effective, other than the Hero of you want soul generation.
On that topic, I’ve been finding that I get around ~40 souls a match, hitting the 60 cap a couple of times. So, less generation than Valkyrie, but significantly more capable versus Impervious teams than a double Mab team.
Frozen is a pain, three red and three purple troops means one frozen unit can be harsh!! I’ve had this happen a couple of times, just kept using Aziris to create skull matches. This meant I still kept doing damage at least while frozen was in effect.
A fun build, with a couple of flaws, but is a capable alternative if people are looking for something other than a blue mana based team.