Magic User Rework: 4 Kinds of Spellcasters.

In the last post we replaced Spell Slots with Mana.

In short:
1 Mana per level, spells can be Bound (memorised) for 1 Mana per Spell Level, or spells can be cast Unbound (spontaneously) at a risk.
Overall you get fewer safe spells per day, but you get far more flexibility and never run out of spells.

Casting Mechanics

I should note that I've changed the base magic rules slightly, mostly for ease of use.

Casting
Declare casting as an Action. The spell goes off at the start of your next turn. During casting you count as Surprised against all attacks.

Changed from "Declare before initiative is rolled, spell goes off at the end of the round". I kept forgetting to ask people to declare spells. Since initiative is rerolled every round, this could get crazy...

Interrupted Casting

If you are damaged mid-cast there are consequences based on your character class.

Down from "if you are damaged or attacked in melee", because if a creature can't hit a wizard standing still with a melee weapon they don't deserve to disrupt anything!

Exp Tracks
All casters - even Elves - use the Magic-User exp track.

Since Elves are on an even keel with the other casters at this point, it seemed unfair to penalise them.

Alright, on with the show.

Caster Classes

I've got 4 Chaotic caster classes in my game.
I could just have each class use the exact same core mechanics, but I like the idea that different casters feel different in play and encourage different gameplay styles.

Magic-User: The flexible caster.
The main focus of the Mana system.
Bind spells for safe casting, access to Cantrips, and the ability to create Familiars.
Leave Mana Unbound to cast spontaneously.

Muscle Wizard: The frontline caster.
Increased survivability since Bound spells boost HP and melee attack, and spells are instant-cast so can't be interrupted.
Unbound Mana might be used to overload a powerful punch attack, and spontaneous casting means you could cast more than one Magic Missile Punch per day.

Elf: The spontaneous caster.
Defined by their Heartspell - a level 1 Spell that defines their Elf species.
Cannot Bind Spells, so they always cast spontaneously unless they're casting their Heartspell. Very chaotic!
Spooky Elf powers boost your Heartspell or grant special abilities, but are lost as you spend Mana.

Necromancer: The Vancian caster.
Work best when they do the traditional Vancian memorise-spells-at-start-of-day thing.
Can Unbind spells to do AoE damage, and use Unbound Mana to cast Subjugate Dead.
Reliant on spell components for many of their spells.

Magic-User

Bound Spell Perks:

Cantrips: 

You can tap into the power of Bound Spells for minor magical effects. 

For example Sleep might be used to make someone yawn, or Magic Missile could be used to improve your aim.
When you cast the Spell, you lose access to its Cantrips.

Familiars: 

When you Bind a Spell you may form it into a Familiar.
Familiars are smallish creatures on-brand for the spell - like Shield could be a hedgehog or Spiderclimb might be a spider or gecko.
When you cast a Familiar's spell, you can cast it through that Familiar if you choose. It vanishes once its spell is cast.
Familiars can communicate mentally with you, will obey simple orders, and cannot be harmed.
If you die, all of your extant Familiars go rogue - each erupts as a Summon spell with HD equal to Spell Level and runs amok!

Interrupted Casting:

Bound Spell:
If damaged during the casting of a Bound Spell you release a Chaos Burst.
If you wish, Save vs Chaos to negate the Chaos Burst and re-Bind the spell, effectively putting it back in your head like you hadn't tried to cast it. Otherwise the spell fails and is lost.

Unbound Spell:

If damaged during the casting of an Unbound Spell you risk disaster.
When the spell goes off, roll on the Chaos Conduit table an additional time for each instance of damage. Take the worst result.

Notes:

Themes:
Magic-Users are flexible and the most easily re-themed into a Witch or a Sorcerer or Druid or whatever kind of archetype you like.
Cantrips give the player a lot of leeway to get imaginative with minor effects. As a general rule of thumb these should be about as powerful as the classic (non-5e) cantrips like Blink or Bee.
Familiars have been in the game for a long time, but previously they've been a permanent animal companion who can hold an extra spell. Now they are spells and I'm quite excited about it! If a wizard shows up surrounded by a menagerie you'll know they're dangerous, and also maybe have some hints as to what spells they're packing.

To Bind or not to Bind?
Magic-Users have the most obvious risk/reward to Binding spells.
Bind them for the Cantrips, Familiars and safer casting, or leave your Mana unbound for flexibility.

To Cast or not to Cast?
Similarly, if you've Bound some Spells you have another obvious choice - keep the spell Bound for the perks? Or cast it for the immediate benefits?
We've had one Wizard who kept hold of Magic Missile forever instead of casting it because he liked using a Cantrip that gave him a bonus to Aim.

Interruptions:
Bind a Spell and if you're interrupted the spell is cancelled no matter what, but you've got a chance to retain the spell for later.
Cast spontaneously and there's at least a chance that you'll cast the spell regardless - pour enough Mana into a spontaneous cast and it's impossible to stop it from going off successfully.

Muscle Wizard

Bound Spell Perks:

Muscle Magic:

Your fists are d4 Shanky weapons, and can be dual-wielded (naturally).
Each Bound Spell improves your strength and physique.
You gain +2 HP and +1 to melee attacks per Mana committed to Bound Spells.
You lose these perks as you cast the spells. If you reach 0HP from spellcasting, you fall unconscious from overexertion.

(Un)interrupted Casting:

I Cast Fist:
Your spells are cast instantly via punching, so you can never be interrupted!

Close Range Caster:

Ultimate Muscle:
The maximum range of a spell is 10' - extra distance you run or jump or flash-step to the target - and you are never affected by AoE from your spells.
When you cast a spell you must combine it with an unarmed attack that automatically hits for maximum damage, plus bonus damage equal to Mana consumed in the casting.
You can target yourself or your punched target with the spell, so if you want to target yourself it's best to target an enemy but perfectly ok to punch a wall or small animal or something.
On the other hand, if you want to cast a buff spell on a friend you'll want to make sure they don't have a glass jaw...

Notes:

Themes:
Obviously the Muscle Wizard remains one of the sillier classes, but I've always been pleased by how they work in play compared to a regular M-U. Especially since I've got fond fond memories of POWERLAD.
The theme is obviously to PUNCH. They've got frontline combat buffs, and since they snap-cast their spells they're less vulnerable than other casters in the thick of it.
A new change is that they have to combine a spell with a punch attack. Previously damaging your target was optional, and I'll be interested to see how this works out.
Since Mana is limited compared to Spell Slots, each Mana committed to Bound Spells gives +2 HP. This works out better for the MW in early levels and gets to be on-par with the bonus HP of the previous version by level 7, which is a sweet spot. Plus their attack bonus grows quicker.

To Bind or not to Bind?
Muscle Wizards will usually want to bind all their Mana into their muscles to increase their power and reduce their squishiness.
On the other hand - spontaneous casters can cast in armour and Muscle Wizards can't be interrupted, significantly reducing one of the main risks! I kinda dig the idea of an Armoured Muscle Wizard and the Muscle Wizard's low AC has always been a weakness, so this could shift the balance.

To Cast or not to Cast?
Always a straightforward class - the Muscle Wizard has always had to decide between keeping their spells back (for the HP and attack bonus) and using their spells for immediate effect.

Elf

Heartspell Perks:

Heartspell:
There are 20 species of Elf. Each has one of the standard first level spells as their Heartspell.
It defines their species - the mutations and abilities they gain from the magic infusing their magical forms. As they use their magic, flinging it out into the world, they slowly regress back towards that feeble mortal form.

For each point of Mana in the Elf's Mana Pool, they gain an additional power and mutation from their Heartspell. Current document is here. They lose these gifts as they use up Mana.
When an Elf has 0 Mana in their Mana Pool they lose access to magic - they are human again.

Moondancer:

Elves do not sleep. They regain their full Mana Pool after dancing under the moon for an hour per level. If prevented from doing this somehow, they do not replenish their Mana.

They gain +1 to their maximum Mana Pool when they dance under a crescent moon, and double it under the New Moon.

They take -1 to their maximum Mana Pool when they dance under a gibbous moon, and halve it under the Full Moon.

Casting:
Elves cannot Bind spells. They must cast spontaneously (with all associated risks) if they want to cast anything but their Heartspell.
Their Heartspell, by contrast, is easy. It can be cast instantly as an Action. When they cast their Heartspell the Elf must Save vs Chaos - on failure they spend 1 Mana, otherwise they cast the spell for free.

Interrupted Casting:

Heartspell:
Since a Heartspell is cast instantly as an action, it cannot be interrupted.

Unbound Spell:
If damaged during the casting of an Unbound Spell you risk disaster.
When the spell goes off, roll on the Chaos Conduit table an additional time for each instance of damage. Take all results, but successes don't stack.


Notes:

Themes:
Elves are all about the creepy fae vibes.
Forcing them to be Spontaneous Casters feels thematically on-brand, as does giving them potentially infinite casts of their core Heartspell. Around Elves, watch yourselves.
The effect of the Moon is more powerful than it was in the past, so Elves would do well to ensure they're paying attention to the moon phase. Due to certain incidents my campaign's moon is in a close orbit so you get 2 moon cycles per month. More opportunities for moon madness!
Since Mana is doubled at the new moon, Elves can reach higher power levels more quickly. Exciting! And it forces me to bulk out the Heartspell power list quicker.

To Cast or not to Cast:
Elves, unlike other casters, completely run out of magic when they run out of Mana.
They also gain far more from retaining their Mana than the other classes - powers and mutations that give them cool abilities and make their Heartspell more powerful.
The choice is then - keep my powers? Cast my Heartspell and risk losing a small part of my abilities? Or weaken myself for certain by pouring Mana into a regular spell?

Interruptions:
Heartspells are cast instantly - they're a safe option.
Unbound spells are far riskier. Interruptions risk chaos, but also some certainty. If you've already rolled a Success then you know the spell will go off. The issue is you don't know how many side effects you'll be facing...

Necromancer

Necromancer Spells:

Voice of the Dead:
Many Necromancer spells and abilities require spell components. The most important component is Last Breath - the final breath of a sapient being. These are usually stored in glass vials, and breathing in a Last Breath grants you the Voice of the Dead for ten minutes.

Lesser Dead:
There are three basic flavours of 1 HD Lesser Dead, available to all Necromancers.
Skeleton: Can use weapons. Take 1 damage from non-Smashy attacks.
Zombie: Double HP. Slow - acts at the end of each round. Becomes an area of damaging zombie bits when killed - dealing 1 damage to anyone standing in it. Becomes a fast, intelligent Ravenous Zombie if it eats a brain.
Skin Kite: Doesn’t obey orders. Real bastard. Flies slowly. Takes 1 damage from Smashy attacks. Grapples fleshy targets, dealing 1d6 damage and healing itself to 6 HP per successful Grapple.

Master of the Dead:
Necromancers have the innate ability to raise and control the Dead. Each of these abilities requires the Voice of the Dead.
Animate Dead: Spend X Mana, raise that many lesser Dead minions. Takes 10 minutes.
Subjugate Dead: Spend X Mana, roll Xd6+level and Subjugate that many HD of Dead, weakest first.
Command Dead: Free action. Give your undead orders. Complex orders take a whole Action instead.

Bound Spells:
Necromancers use a unique Necromancer spell list (first couple of spell levels converted for use here based on the book here)
Spells must be Bound to be cast - Necromancers cannot cast spells spontaneously. Unlike other casters, you can bind more than one copy of the same spell.
In addition, many spells require the listed ritual components.
Binding Spells takes an hour. Spend X Mana and bind that many spells. Mana spent this way is lost until the spell is cast.

Casting:
Spells take a round of ominous chanting and rattling and summoning up the souls of the Dead.
Declare you are casting as an Action and the spell goes off at the start of your next turn.
Traditional: Cast the spell and lose it from your mind. Sacrifice 1d6 HP to retain the spell if you wish.
Mana-Boosted: Spend Mana to cast the spell. You retain the spell and count as casting at 1 level higher per Mana spent.

Interrupted Casting:

Death Burst:
If you are damaged while you are casting a spell, A burst of death magic deals 1d6 damage per Mana spent in the casting to you and everything with 10’.
Undead are healed for the same amount.
You lose the spell unless you cast a Save vs Chaos.

Notes:

Themes:
Thematically, Necromancers are encouraged to be careful and plan ahead. If they want spells they need to pack them in advance, otherwise they have to fall back on basic dead-raising Necromancy.
Last Breath is a commodity in the post-apoc economy because there are so few people left, so people use it as a currency. Pretty macabre.

To Bind or not to Bind?
Do you keep your Mana unbound so you can cast your Dead-affecting spells? Or do you bind it into spells, reducing that option?
Once you've bound a spell you can cast it over and over by sacrificing HP, so that's good.

To Cast or not to Cast?
Since there's no passive benefit to retaining spells, the question is more how to cast.
Do you cast it once and lose it from your mind? Or go full blood magic and power the spells with your HP? The choice is yours!

Gimme the Full Thing Already!

Full text, with the "Core Mechanics" integrated, is either in the player-facing Quick Class Breakdowns booklet, or in the latest House Rules Document.