I'd like to keep up with the weekly progress update. It might not look like much, but there was a TON of under the hood changes. The new system will make implementing new custom spells far easier and with minimal bugginess while maintaining the flexibility I desire in such systems. Now that it's actually done and bug free, I can crack out the rest of the original spells into the new system.

0.03 Changelog

Mana System Implemented

Mana System
-All heroes now have mana as one of their properties to use on spells and abilities.
-A hero's current mana amount replaces the hero's current number of Healing Potions on the UI.
-Heroes can still purchase and use healing potions. Whether a hero has any potions will be shown in their inventory screen as an Item now.
-Healing and Mana Potions can now be seen in the inventory along with how many of each the Hero has.
-All hero's have a base Max Mana of 5 assuming 0 Intelligence.
-Cooldown for most hero spells will be adjusted accordingly to balance between mana cost and cooldown.

Spell System
-Improved spell target prioritization for heroes attacking buildings. (Heroes will switch to attacking any enemy units that come within range while attacking a structure.)
-Spells in this system will no longer stack on simultaneous casts (Charm Animal won't have 5 charm buffs on an animal if 5 Cultists get to it at the same time).

Spell Changes
-Majesty hero spells are being moved to use the new spell system.
-Due to the attribute changes for Willpower, most old spells will have Cooldowns scale differently.
-Spells now have different spellcast ranges rather than being set automatically to the caster's casting range.
-Max Cast ranges have been increased by 50%.
This shouldn't actually affect the cast range of hero starting spells like the Wizard's Energy Blast since their cast range has been adjusted to be a fraction of the Maximum. It will essentially be the same range as it was before, while other spells will now have the benefit of being able to be classified as long-range or short-range spells.
Sight Range has been left the same as it determines the distance at which an enemy is evaluated for a flight or fight response. This allows Casters to bombard targets with long-range spells before deciding if they should fight or not.

Monk Spells
Hands of Steel
-Strength gain changed from 16 to 8 + (Intelligence / 5).
-Hand to Hand gain changed from 25 to 12 + (Intelligence / 4).
-Duration changed from 26 seconds to 20 seconds.
-Cooldown changed from 29 seconds to 10 seconds.
-Range: Melee (Self).
-Mana Cost: 2
-Does not stack. Cannot be cast on allies.

Stone Skin
-Armor gain changed from 8 to 3 + (Intelligence / 7).
-Duration changed from 33 seconds to 27 seconds.
-Cooldown changed from 35 seconds to 18 seconds.
-Range: 50% of Max Cast range.
-Mana Cost: 5
-Can cast on nearby allies.
-Does not naturally stack.
Will cast on the closest allied target if the caster already has the effect on himself.

Iron Will
-Magic Resistance gain changed from 55 to 35 + (Intelligence / 2).
-Critical strike chance gain changed from 6 to 1 + (Intelligence / 7).
-Duration changed from 40 seconds to 32 seconds.
-Cooldown changed from 42 seconds to 20 seconds.
-Range: 50% of Max Cast range.
-Mana Cost: 12
-Can cast on nearby allies.
-Does not naturally stack.
Will cast on the closest allied target if the caster already has the effect on himself.

Wizard Spells
Energy Blast
-Initial cooldown increased by 20% to compensate for long range and new attribute effects.
-Range: 67% of Max Cast range.
-Mana Cost: 1
The Energy Blast range is the same as before since max cast range has been increased by 50%.

Fire Shield
-Magic Resistance gain changed from 25 to 10 + (Intelligence / 5).
-Armor gain changed from 5 to 1 + (Intelligence / 8).
-Duration changed from 21 seconds to 15 seconds.
-Cooldown changed from 25 seconds to 7 seconds.
-Range: 67% of Max Cast range.
-Mana Cost: 4
-Can cast on nearby allies.
-Does not naturally stack.
Will cast on the closest allied target if the caster already has the effect on himself.

Fire Blast
-No longer automatically attempts to cast against buildings and lairs.
-Cooldown reduced from 3.5 seconds to 2.4 seconds.
-Range: 50% of Max Cast range.
-Mana Cost: 6

Fire Ball
-Radius changed from 80 to 70 + (Intelligence / 6).
-Area of Effect damage changed from 2 - 15 to just 15.
-Area of Effect Spell damage is now linked to the casting hero so it will now scale with the hero, whereas before it remained static.
-Reveals the area around the target if it is located in the Fog of War.
-Cooldown reduced from 4.5 seconds to 3.0 seconds.
-Range: 75% of Max Cast range.
-Mana Cost: 9

Resist Magic
-Magic Resistance gain changed from 35 to 20 + (Intelligence / 4).
-Duration changed from 39.5 seconds to 26 seconds.
-Cooldown changed from 41.5 seconds to 12 seconds.
-Range: 50% of Max Cast range.
-Mana Cost: 7
-Can cast on nearby allies.
-Does not naturally stack.
Will cast on the closest allied target if the caster already has the effect on himself.

Attribute Changes

Artifice
-Increases Sight Range of non-ranged heroes by 2 per point.
-Increases Cast Range of non-ranged heroes by 2 per point.
-Reduces the cooldown of magic spells and abilities by 0.75% per point of Artifice.
-Reduces the cooldown of non-magic spells and abilities by 1% per point of Artifice.
Gives melee spellcasters more room to wield any spells before engaging in combat.

Intelligence
-Main attribute governing the mana system.
-Intelligence increases Maximum Mana by 2 per point.
-Intelligence increases Mana Regeneration rate.
-Intelligence gives Mana Potions 1 more point of healing per 4 points of Intelligence.
-Increases the duration of magic spells and abilities by 0.8% per point of Intelligence.
-Reduces the cooldown of magic spells and abilities by 0.5% per point of Intelligence.

Strength
-Removed critical chance increase based on Strength.
Allowing this attribute to affect critical chance made it far too powerful. Critical strike in Majesty means the target dies in one hit.

Willpower
-Changes debuff duration reduction from 1% per 2 points of Willpower to 0.5% per point of Wisdom.
-Increases the effective power of buffs by 1% per point of Willpower.
-Decreases the effective power of debuffs by 0.5% per point of Willpower.
Makes each point of Willpower count while keeping the end result virtually the same.
Effective power refers to all effects other than damage and duration.
Willpower doesn't affect (de)buffs cast from this hero, but (de)buffs cast on this hero.

Wisdom
-Increases the effective power of buffs and debuffs by 0.75% per point of Wisdom.
-Decreases mana spent on spells by 0.4% per point of Wisdom.
-Changed experience reduction from 1% per 2 points of Wisdom to 0.5% per point of Wisdom
Makes each point of Wisdom count while keeping the end result virtually the same.
Wisdom doesn't affect (de)buffs cast on this hero, but (de)buffs cast from this hero.
Effective power refers to all effects other than damage and duration.
Mana Spent on spells refers to the end mana that the hero spent. Iron Will requires a base amount of 12 mana to consider casting regardless of how much Wisdom the hero has, so while Wisdom might reduce the end cost to 7, 12 mana is required for the spell to be considered castable.

Building Changes

Marketplace
-Now sells Mana Potions alongside Healing potions for heroes with spells/abilities that cost mana can buy.
-Mana Potions cost 30 Gold each and heroes can have up to 5 at a time.
-Mana Potions restore 25 + (Intelligence / 4) Mana Points when a hero is low on mana.
-The number of Mana Potions a hero has is displayed in the Inventory screen alongside Healing Potions.

Hero Changes
-General armor decrease of 1 for all heroes with greater than 1 point of Armor from their starting 10 points of Vitality.
Keeps the starting armor for most heroes relatively the same to offset the new bonus to armor received from Vitality in early levels.

Monk
-Primary Attribute has been changed to Wisdom.

Up Next: Moving the remainder of old spells to the new spell system. Adding in a Health Regeneration/Degeneration system to replace the game's built-in Healing Rate and Poison Counter attributes as those have some fairly abysmal limits on their effectiveness. Vitality will increase Health Regeneration rate.

Edit: Added a screenshot to the workshop of what the Inventory screen display looks like with Health and Mana Potions.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=688482919