D&D 5E Caster with access to only one school

[TaranTheWanderer]

A bit off-topic, but I had an idea that I needed to get out of my head...

I think it would be interesting to give casters the option to focus on a particular school of magic. If they do, they get one extra spell slot for each spell level, but that spell slot can only be used to cast a spell from the chosen school. But they also have to choose a school of magic that they cannot learn or cast any spells from, ever...not even cantrips, not even from magic items, not even if they multiclass, not even racial spells or feats or rituals, not even with a wish.

Let the player decide if the juice is worth the squeeze.

This is how previous editions did it. (kind of) I liked it. I find all the casters in 5e are the same. Bard might have the most unique spell list but it's pretty much the same. I was disappointed how 5e divided the Wizard schools.

In my current campaign, schools are grouped in twos into 5 spheres (following the Mystara multiverse model) and each caster must choose a sphere. They are arranged such that one sphere opposes another, so all spells of the two schools that oppose the caster's chosen sphere are all treated as one level higher than normal.

I don't get what you mean...'twos' . Please eloaborate

Right now, I have the following features; I'm modeling it as a custom cleric domain with Knowledge domain as a baseline inspiration.

Can only be taken by a half-elf with the Mark of Detection.

Spellcasting: Can't prepare from the cleric spell list, instead prepare divination spells from any spell list.

Can't use Channel Divinity to Turn Undead.

Gains Investigation and Insight as bonus proficiencies, doubled bonus. (Like Knowledge)

Can use Intelligence instead of Dex for ranged and finesse weapons, and for AC calculations. (We agreed that having a high Wisdom and Intelligence were both important for a magical detective, so some stat swapping made sense here.)

Can use Channel Divinity to recharge their racial Dragonmark ability once used. (I feel like this is a little weak, I may swap this for the Portent ability.)

At 6th, their two divination cantrips get an upgrade. True strike becomes concentration and can last for 5 rounds, it gives advantage on their first attack on each of their turns. Guidance gets bumped up to a d6.

At 8th, they get Divine Strike (they don't have any damage cantrips, so kinda necessary).

At 17th, they get Visions of the Past (as Knowledge).

This seems pretty good. If you are making True Strike 5 rounds, I think it should be concentration. And to be consistent with other spells, it might as well be 1 minute/concentration. Does it trigger every time you attack, or just on the next attack? I'm assuming the latter

 

[TwoSix]

This seems pretty good. If you are making True Strike 5 rounds, I think it should be concentration. And to be consistent with other spells, it might as well be 1 minute/concentration. Does it trigger every time you attack, or just on the next attack? I'm assuming the latter

Yea, the upgrade makes true strike have a duration of "Concentration, up to 5 rounds". I mean, it could be a minute, but I don't want it to be too abusable. I'm OK with doing some non-standard stuff with homebrew for a single character. It would also function on the first attack only on each of the caster's own turns.

 

[FrogReaver]

Divination is going to be combat weak. But dang will it be out of combat strong!

I love the idea and would definitively allow this.

 

[TwoSix]

Divination is going to be combat weak. But dang will it be out of combat strong!

I love the idea and would definitively allow this.

Yea, I agree. The game is going to have 6-7 players, so there's definitely room for characters with specific niches. And the overall feel of the character is very in-line with Eberron tropes, which is great.