My personal view is that while Death magic does have some good stuff it is significantly weaker than Life magic overall. Also alot of it's good spells have been the nerfed over the betas whereas life magic has escaped this scrutiny for some unknown reason.

1 thing that needs to be pointed out is that to get real mileage out of death magic it needs multiple death shards and a caster with good spell mastery - Ceresa is able to use death magic well for these reasons and obviously she should be leveled up as a mage. Because she's so good with death magic, her best spell Dirge of Ceresa has been heavily nerfed to the point where it's beginning to be overshadowed by horrific wail, which I fear will also be horribly nerfed too in the near future.

Tactical Death magic frequently has casting times and involves resistance checks so spell mastery is extremely important to overcome these uncertainties. It also lacks the utility of life magic as most the spells revolve around damage and curses. It certainly has its merits but there are several poor spells and overal Life magic is more effective IMO. I'll go into more detail about each spell shortly.

fantastic post, you really took time to find the numbers and I will take my time to give my sincerest thanks!

I am pretty tired ATM so I will just agree with death magic needing a little of the violent power spells from life magic

Death magic need some city buff to counter the aura of vitality in life magic (Imo), meaby some dodge, or bonus accuracy to trained units.

And blindness should not be half the targets accuracy, I think it would  be better designed if it was a fixed amount
Blindness, Cost 8 mana: Reduce target's accuracy by 10, + 5 per death shard. (To fit the current scaling).
pick some different numbers, just the idea behind it

Right now Blindness is the ONE spell in death I would cast, also because it stacks in an overpowered fashion with "Krax's" ability to spawn a +30 dodge field.

I also really need some proper level 1 spell, a spell I can use when questing/levelling, berserk I really hate, and wither is too expensive.

Death do have some potential powerhouses among the spell though.
powerhouses:
Blindness (ofcourse) this spell will cut through big frightening opponents, and smash the "Maul" ability, also stacks too much with dodge.

Wither, this can really "ruin" a teamfight, take a fight where I have 2 death shards, I will lower each trained unit's attack by 4, this is really alot when you think about it.
Kill, if you pick "brilliant" for way more mastery, this is a 300 mana freekill for wildland bosses (and tons of xp to the group following, if you bring 8 trained unit, and go in and blast the big boss with Kill, you could potentially have a killer group. Suffers from a high mana cost due to path of the mage, and lucky drops can lower mana cost of spells by thirty-fourty percentage.

Sincerely
~ Kongdej

ah yeah i forgot, many death spells need scaling, they really do need it

blindness is cool like you propose, even curse could be 1 turn + 1 per 2 death shards etc etc

hence why I think Death > Fire  > Everything else. 

One problem with death magic that I have is the lack of summons.

Maybe the devs did not want to get into "fantasy cliches" much, but I figure that death magic would be the reanimation spell system. Whereas life magic "heals," death magic reanimates temporary soldiers.

Perhaps a tactical-only summon spell that can be cast repeatedly. It would summon weak units, but those units would be expendable meat-shields.

Some ideas:

Level 1: Summon wild zombie - Tactical spell only. summons a temporary wild creature for this battle. May be cast multiple times (summons include wolves, ogres, bear cubs, bears or stalkers chosen at random).

Level 2: Reanimate unit - grants target trained unit temporary hit points until the end of combat (giving extra soldiers in the squad) equal to X times X number of death shards. Temporary hit points are lost at the end of the battle. Spell may only be cast on wounded units.

Level 4: Summon zombie army - Tactical spell only. summons a 9 person "militia" type unit armed with clubs. Unit hit points are X times X number of death shards (should start out low to balance the higher unit count. May be cast multiple times.

Level 5: Summon vampire - (this may not be feasible to implement, depending on how much content the devs are willing to add to the game at this point) Creates a unit that drains health every time it attacks. 

Death Tier 1:

Unfortunately wither has been nerfed several times now and the current spell is pretty weak - the attack penalty is so small now that it doesnt make much of a difference - Ceresa can make better use of it but it's no good without several death shards. The strategic version bypasses resistance checks which is nice but the effect is still very minor. Another thing to remember is that this has no effect on magic based damage so mage units are totally unaffected by this.

Beserk feels too weak to me and I actually think its better not to cast it in 9/10 circumstances - poisoning your unit for a negligable attack bonus feels like a bad deal and it becomes unplayable on the harder settings where the AI's bonuses make each battle a slogfest. This spell is supposed to be the death opposite to regeneration but it really needs a boost.

Death Tier 2:

Blindness is a saving grace for death magic it's cheap and very effective IF it sticks - like all the curses it relies on spell mastery.

Curse is also pretty good too so Death2 is worth picking up.

Death Tier 3:

Antipathy has dropped in price from 100 to 30 which seems much better and I can see myself using this spell occasionally on the harder settings although the effect is pretty tame and I agree with Heavenfall that it should scale with further death shards.

Blood sigil, hmmm I like the concept however I think both beserk and wither need a boost, once these are improved then blood sigil will also benefit.

Drain life is the only lifegain spell in death and it feels weak to me - it's quite pricey and has a casting time and doesnt deal or gain much life either, especially if the spell is resisted - needs improvement or a cost reduction I think

Death Tier 4:

Mass curse is a nice upgrade to curse although I think they should also double the duration of it's effect to 6 turns as it's 2 tiers above curse and costs three times more mana so it should be a little more potent

Pit of madness is a great concept but I feel it should get a little bit extra as I currently opt for inspiration over this every time and really it should be the other way round as this is tier 4 and inspiration is available from turn 1. Minus 1 growth is a pretty hefty penalty that can sometimes completely stall growth in a city so what I propose is that in addition to the research benefit and cloak of fear, this spell also gives mana per essence too (i.e. it combines meditation with inspiration and the cloak effect but penalises growth)

Touch of entropy is expensive but does deal alot of damage and spawns a decent unit too - Ceresa is very good with this. I would like the lurk to be permanently gained and stick around after the battle too. This makes the spell more interesting and I feel Death magic needs some more nods towards the necromancer trope. How about giving the lurk the harbringer perk too?

Death Tier 5:

I currently don't bother with picking up death 5 even with Ceresa because there's nothing worth picking up from this tier.

I think bloodrage and all it's cousins are a total waste of mana - I know someone will pipe up and tell me it's a mana sink and isnt supposed to be any good but I don't accept that argument. This spell is a ) boring b ) so marginal as to be irrelevant.

Sacrifice generates more mana now which is good to see and given that population has limited impact (levelling up & tax) I can see myself using this sometimes. You could actually kill pretty much all the population once a city hits level 5 and just suffer a minor tax penalty so this spell can potentially generate alot of mana although it feels a bit cheesy to do this (you'd think the population would object to being sacrificed really).

Kill seems far too expensive to me - 300 mana plus skipping 2 turns makes this almost unplayable except maybe against uber bosses. If they make a resistance check you have wasted 3 turns and 300 mana for nothing, awful. Other cheaper spells get the job done for a fraction of the cost and the uber bosses have a good chance of resisting this spell - I would never use this spell in it's current form, ever.

Ceresa's spells:

Infection - a nice little spell though in practice I don't use it often

Corruption - this is excellent and helps to scale up all otherwise weak spells so that they become good - at 50 mana I feel it should auto upgrade the resource too though

Graveseal - excellent spell, the best curse of them all

Dirge of Ceresa - I think this has been the most nerfed spell and people are calling for it to be nerfed again - no more nerfing please as I'm often choosing horrific wail over her signature spell when playing Ceresa

Combo spells:

Contagion - this has been nerfed really heavily too, I'm not sure if it's playable anymore as I haven't used it in a while

Horrific wail - this spell is good in the hands of a mage caster with a few levels under their belt - I'm hoping they don't nerf it but unfortunately any good death spell seems to be nerfed eventually

Soulburning - this is a good spell although it becomes overshadowed by flamedart at higher levels - I personally think this is fine as is

Syphon strength - a decent curse/buff - it feels fine as is