Saturday 11 March 2023

Spell Casting in Melee


When I returned to playing AD&D, my memory of how spell casting worked in melee went something like this; if you won initiative your side's spell(s) go first, if you lost the other side's spell(s) go first, and of course, on tied initiative they happen simultaneously. But, what do the rules actually say? Quite a bit more than that. It starts out in the DMG on page 63, looking much like I remembered, but the succeeding pages detail exceptions. There are two discrete sections covering the topic: one, covered under "SPELL CASTING DURING MELEE" on page 65, is concerned with attacks at range, and the other on page 66 covers melee weapons with a speed factor "with respect to opponents who are engaged in activity other than striking blows". In this post I will concentrate on the former only, since it is complicated enough all by itself.


These functions are fully detailed in PLAYERS HANDBOOK. Their commencement is dictated by initiative determination as with other attack forms, but their culmination is subject to the stated casting time. Both commencement and/or completion can occur simultaneously with missile discharge, magical device attacks, and/or turning undead. Being struck by something during casting will spoil the spell."

Paragraph 1

This paragraph (P1) is crucial for understanding the rules that follow it on p.65 and later. Note, given that all spells have a casting time, and missile weapons do not have weapon speeds; the question arises of how can it be possible that they occur simultaneously? This question is addressed obliquely below:

"Attacks directed at spell casters will come on that segment of the round shown on the opponent’s or on their own side’s initiative die, whichever is applicable. (If the spell caster’s side won the initiative with a roll of 5, the attack must come then, not on the opponent’s losing roll of 4 or less.) Thus, all such attacks will occur on the 1st-6th segments of the round." (ibid)

                                                               Paragraph 2

Paragraph 2 (P2) obviously has a critical bearing on who goes first, but it is cryptic. How do we determine which is the applicable initiative die? Why will all attacks occur only in the first 6 segments of the round, when we know many spells have a casting time greater than 6? To help here, since spells are described as another “attack form” in P1, we can see that P2 must be read in light of P1. So, for the purposes of this discussion, an "attack" can be either: a spell, a missile weapon, a magical device, or turning undead.

Additionally, I'll use "casting time" to refer broadly to the number, in segments, required to complete an "attack" as defined above. Spell casting usually takes between 1-9 segments, missile fire requires 0 segments, magical device attacks usually require 2 segments, and turn undead requires 0 segments. Again, the possible interruption of spell casting by melee weapons is covered by different rules on the next page of the DMG and is beyond the scope of this discussion.

"Thus, all such attacks will occur on the 1st-6th segments of the round"

I think the final sentence of P2 above should be read as: "all such attacks will commence on the 1st-6th segment", and, since we know from P1 that spell "culmination is subject to the stated casting time" culmination requires that the casting time also has elapsed. So, a Fireball spell (casting time 3 segments), though it may commence in segment 4 based on the initiative die, would culminate in segment 7.

The question now becomes: which is applicable, "the opponent’s or (...) their own side’s initiative die?"

In my view the answer follows from the fact that a caster begins casting a spell as "dictated by initiative determination" (P1). This means that once initiative has been determined the winner is deemed to have started casting; his spell then culminates in accordance with its casting time without further reference to either initiative die.

For the initiative winner's spell attack to have a possibility of being interrupted, attacks that could do so must not simply "commence" but "culminate" first. The initiative loser's attacks culminate based on the their opponent's initiative die roll added to their "casting time";  and are evaluated in order from lowest to highest. It will be seen that sometimes the totals may be equal to the winner's casting time, in which case the attacks happen simultaneously; and this is how arrows in flight can be consumed by fireballs.

Given the above, the applicable die therefore is the winner's die; in the case of ties this number is used by both sides to determine when their attacks culminate. Again, the attacks of all the characters in both parties culminate and are resolved in the order of these totals and any casters who are damaged before their turn in the sequence have their spells ruined.

In light of the above, returning to P2, one way of rewriting the specific example there into a general rule would be:

#1 If a spell attacker won initiative, then any opponent's attacks on him will commence on the segment corresponding to his initiative die roll. The winner's attack will culminate on the segment corresponding to its casting time alone.

Note: if the winner's casting time is less than his initiative die roll, his spell will always go first; if equal it will go simultaneously with 0 casting time attacks; if greater then his spell attack may still culminate before an enemy caster, depending on the enemy's casting time.

It would follow that:

#2 If a spell attacker lost initiative, then his attack will commence on the segment corresponding to his opponent's initiative die roll, and will culminate on the segment corresponding to the die roll plus his casting time. His opponent's attack will culminate on the segment corresponding to its casting time alone.

Note: the initiative loser may still be faster than an enemy caster but enemy attacks with a casting time of 0 will go before the the initiative loser no matter his spell casting time. If there is no enemy attack with a casting time greater than 0, then the calculation of which segment the initiative loser's attack commences on is no longer relevant.

#3 If a spell attacker tied initiative, then both his and his opponent's attacks will commence on the segment corresponding to the number rolled on the dice. Each attack will then culminate on the segment corresponding to its casting time plus the number rolled.

Note: since spell casting takes minimum of 1 segment, for a spell caster this has the same effect as a losing result against enemy attacks with a casting time of 0.

More than 10 Segments?

It will be seen that the totals of initiative die roll and spell casting time may easily be greater than the 10 segments that are supposed to comprise a combat round. However, since the 1 minute combat round is an abstraction, for the purposes of attack order determination I believe any talk of things happening “on a segment” is meant only loosely and can be jettisoned completely in favour of just comparing the relevant totals.

Why is it so?

The casting of spells in melee is described as a tricky proposition and very much discouraged, and the rules reflect this. The mind boggling rules boil down to a relatively good chance of successfully casting a spell if you win initiative, yet they still give the loser a chance if they have chosen a fast spell.  The main benefit of the complicated resolution is to give casters a more nuanced choice at the beginning of the round when they must declare their spells; do they choose spells that are fast enough to go first on a winning but low initiative roll, or go for broke on a longer casting but more powerful spell. Like many AD&D rules, you might go many sessions with them being needed; but, for example, a caster duel with this rule in play makes for some very interesting choices.

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