Anyway from my point of view the lore of incantations.
The thing to note against tomb kings I the fact all there 'wizards' count as casting a bound level spell (level is XD6 depending on who it is)rather than a actual spell so there is no miss casts or irristable forces- that’s both good and bad.
Second is that all but 1 hero/lord can cast magic, yep tomb princes and tomb kings can also cast two spells of the list .
Also the 'wizards' have to cast in a set order, I can't remember exactly what the order is but its needs be the same every turn.
In terms of dice this is what each modal gives.
Tomb prince-power level D6- own unit only- 1 incantation a turn.
Tomb king- power level-D6-own unit or 6"- 2 incantations a turn (may be same).
Liche priest- power level 2D6-range of spell-1 incantation a turn.
Liche high priest- power level 3D6-range of spell- 2 incantations a turn.
Incantations
Incantation of Vengeance 2*

This is a magic missile that has an 18 inch range and does D6 4 hits,
not going to do a lot of damage but may be useful to stop if it takes a rank of you targets your war machines.
Incantation of Righteous Smiting 1-5*

This can be cast on either a missile unit or a unit in combat, it either allows them to shot in the magic phase or have 1 attack per modal in the shooting phase, depending on what its cast on it could do very little or a lot, if cast on a unit of 3 chariots not in combat then leave it (3 bow shots aren’t going to hurt) however if its cast on the screaming skull or a nasty unit in combat then dispell it as it could do a lot of damage.
Incantation of Summoning 3*

This is the tome king bring back the dead spell, unlike the VC spell it can only bring back modals not create new units, most units get D3 wounds back, tomb guard get D6 and warriors get 2D6 and pick the highest back.
can be nasty if they use it on warriors and get an extra rank or something similar.
Incantation of Urgency 5*

As most people have said before me movement spells can win game, this allows the unit to move again.
Stop it at all cost as most good players will use it to set up flank chargers, and as most people will tell you getting chariots/ushanti/bone giant to the flank hurts so watch it.
You can let one unit use it the get them out of place and dipel the rest but most of the time stop it .
Also I’m going to put one last bit to this.
That is the Casket of Souls, the most dangerous bit of magic kit the tomb kings can bring.
Counts as a bound item which is cast as power level 2D6
what it does is every unit (not the tomb kings them selves) have to 2D6+2-units Ld in wounds with no armour saves, stop it at all cost.
Edited for spelling and grammar - LF