Just been having this discussion on Skype with some friends, what was the first video game to feature a mana pool?

That's actually a good question, most early RPGs co-opted D&D;'s spell system of charges instead of a mana pool.

The first that springs to my mind is Diablo, but surely there was one before that?

Not sure about first game to include it (magic cost in points, recharge mechanism; older than Diablo) but the idea and design is pre-games so if you want an origin point then it's Larry Niven (AFAIK, a quick wikipedia search seemed to confirm the tale I'd heard for where the idea came from).

A quick dive into the half-remembered past ("haven't all video games used mana?" Oh, I guess I'm just adding that to my old memories, I guess some games without the D&D license used spell/day) and I'm thinking it could be 1985. It could easily be before then (going back into the 'games I haven't played and was quite possibly not alive for their release' section of retro) but The Bard's Tale had a recharging, pointed mana system for magic characters to spend on spells (from vague memory combined with screenshots to confirm, but I haven't played it in so long that maybe I'm getting that wrong) and was before Dungeon Master (a couple of years later - and that definitely has spending mana points on magic spells as you inscribed their runes. Was it cost as number of runes so longer spells cost more of am I getting that wrong?)

The first Final Fantasy in 1987 had magic points, I think.

@McGhee said:

The first Final Fantasy in 1987 had magic points, I think.

No, it used a system where you could only have nine spells of each level. Some of the remakes have changed this to a standard mp system.

Doesn't Ultima 3 have a magic pool? That's 83'

didnt zeldas magic system have a "mana pool" of sorts

I remember Dragon Warrior using magic points or MP (released in 1986 in japan)