doctorbadwolf
Heretic of The Seventh Circle
I think the answer is a lot less than with the use of invocations, at least as far as adding some choice goes. If what we want is the standard power at 3rd, power at 9th approach, etc then it's easier to envision because it's only four abilities. If you gate abilities behind x/day or x/rest and provide some choice inside that ability you still get options and flavor without leaning on a spell-like mechanic. Multiple options for one ability or invocations probably gets us to about the same place though, so maybe we should hash out some specifics on abilities and then figure out how to implement them?
Standard Archetypes generally get two light or one heavy ability at 3rd, and then one heavy at 9/13/17. Is that the rough template we want to start with?
I'd go with the multiple light abilities at 3rd so we can splat the theme a little wider. Generally there's a movement or maneuver ability and then something with sneak attack. We might reasonably up the power level a titch if the abilities only work in dim light or darker.
Maybe something like this:
Movement (Shadow Dance?): when in dim light or shadow, the Shadow Dancer gets an additional 10' of movement and X. That second part could be advantage on athletics/Acrobatics; don't provoke attacks of opportunity; stuff like that.
Attack: when in dim light or darkness the SD get advantage on the first round of combat unless they already have disadvantage. I'd like a defensive thing in here too, something shadow-formy. Maybe call it a bonus action so it's more of choice rather than a constant mod. Maybe the bonus action grants you +2 AC for the rest of the round? Something like that - essentially it works as an additional option for cunning action. Maybe +2 is too much, IDK, that was just the number that came to mind. If this sounds like it's too much you could gate some or all of it behind, say, an Performance check (that's the shadow dance) DC whatever, at which point I'd grant Performance proficiency at 3rd as part of the Archetype. You could even add some extra effect for higher DC checks, which essentially makes the abilities scale by level, which is neat. That would get us that 'invocation' feel without using those rules, and we've added a check to help balance the strength of the skills.
I'm going to stop there. Let me know what parts of that catch your fancy and we'll keep hacking away.
Okay I think Performance is good, and bonus expertise if already trained in it? Idk
For movement I’d maybe give jump distance set by your Dex instead of Strength score in addition to speed boost? What about something similar to Bladesong, that has to be activated? Either way, I’d prefer it have some small benefit even in bright light, but maybe I’m being too wary of situational benefits.
I’d be down to keep the combat benefit more on the defensive side, and give a Shadow Armor benefit, but I’m also willing to leave that for level 9?
Perhaps a flat bonus to speed and jump in dim light or darkness, proficiency in performance, and a Shadow Dance ability 2/SR, bonus action.
Shadow Dance: AC boost (+2 or +a stat?), Advantage on Stealth, ability to dim lights around you, and you can SA while in dim light or darkness (teleport 30 feet as a bonus action while active too much?), no OAs when dashing, stuff like that. Your movements and being wrapped in shadow protect you. You become partly shadow. Etc.
level 9, Shadow Dance now includes a Shadow Blade style benefit? Or tenebration?
Level 13, something out of combat. Phasing? Shadow scrying?
Capstone: Insubstantial while in Shadow Dance, or create a shadow duplicate that fights with your AC and Attack and Damage, can deal SA 1/turn, half your HP?