Someone stop the wizard!

The wizard sees the intruders coming from the front door. With a malicious grim, he raises his hands and utters strange words from a long-forgotten language, summoning the dark spirits of the Abyss, as black clouds appear beside him. There is no time to run, nowhere to hide, so the adventures quickly move forward, with weapons drawn, as they try to avoid the evil minions and reach the sorcerer while they can still stop him. Their fate - and the fate of the whole realm - hinges on the very few seconds that the wizard takes to complete the unholy spell.

After doing some quick brainstorming on initiative, I couldn't stop thinking about the subject. It took me a while to understand why. As I've said before, I don't usually appreciate heavily detailed initiative rules - giving initiative based on the situation or in order of DEX is good enough for me.

Still, there is some ideas I like about “segment” initiative that are hard to find (or not as interesting) in simpler systems. The main one, as you may have guessed, is stopping a wizard in the middle of a terrible spell.

The trope is quite old and justifies a few other things I like. For example, you can have earth-shattering spells that do not make the fight one-sided, and that are very risky for the wizard himself (because he can be stopped mid-spell, and lose  the spell - not to mention his life - in the process). Spells get to be amazing being too "unbalanced".

Most important, this forces characters (PCs or NPCs) to work together. For wizard PCs, spell-casting is no longer a solo game, but a tactical group effort, with the mighty fighters protecting the frail wizard to allow him to finish the spell. For wizard foes, the PCs must find creative ways to stop their spells - maybe throwing weapons (improvised or not) at him, or just getting out of the way.

... and sometimes you just have to play dirty.

The whole concept of interrupting a foe action is interesting to me, not only in fiction and tabletop gaming, but also in video games (from Street Fighter to Dark Souls), real MMA fights and so on. Stopping a charge with a spear, stabbing a strong foe the moment he raises his two-handed axe, tripping someone as he runs towards an ally, shooting an arrow before being smashed by a mace (and vice-versa) and threatening an enemy with a blade to the throat are some of the things that I feel are missing from many of the simpler initiative systems.

This, in a nutshell, is why I want a detailed initiative system for my game, and what I'll try to do next.