help with some homebrew sentient magic items

[Kelik]

Context:

so in my setting, the evil king has an elite army called the Hallowed Shields, which is divided into 5 branches, each based on a player class/role in combat. the leaders of each of these branches are high level recurring villains in this campaign. they were once a good army, but became corrupt over time. each of the original founders of the five branches sealed their powers and consciousnesses in soulgems that can be slotted into equipment to make sentient magic items. the players are being tasked with finding each of these gems to gain an advantage against the Hallowed Shields. the five branches are the Defenders (based on defensive devotion paladins), Inquisitors (based on Assassin Rogues), Battle-priests (Based on Death/Trickery Clerics. originally they were Life clerics, but corruption over time changed their allegiances), Spellswords (based on bladesinger wizards from sword coast adventure guide) and Crushers (Based on berserker barbarians).

What I want from these items:

each item is a sentient gem that must be slotted into specific types of equipment in order for its effect to take place. each gem has 6 levels of compatibility, from -1 to +4. each one requires two attunement slots.if it hasn't been attuned yet, it acts as a magic item +1 of it's type. if it has been attuned before and lost attunement, it acts as a magic weapon equal to the bonus it had during its last atunement, if it was at 0 or -1 it acts as a mundane version of the item. if at -1 compatibility, you cannot break attunement with the gem unless the spell "anti-magic zone" or "wish" is used. also at -1 compatibility you have disadvantage on all rolls involving a d20. at 0 compatibility the equipment functions as a normal piece of equipment, other than being sentient. at +1 and higher, it functions as a magic item of the appropriate number, and has two additional effects unique to the item, that scale up as the compatibility increases.

each gem has an effect that is based on the branch of the Hallowed Shields that it came from, as well as a second effect that is meant to counter the abilities of another branch, this was originally intended to allow the leaders to police each other and prevent corruption, though the Hallowed Shields eventually became corrupt after the gems were lost anyway.

each gem is found already slotted into a piece of equipment, and has a list of equipment types it can be slotted into with the help of a blacksmith. this is a safeguard in case one of my player characters dies and rerolls as a different class that may not be proficient in the equipment type.

what i have so far:

Crusher Gem:
meant for: Fighter/Barbarian
found in: Greatsword
Can be slotted into: Two-handed melee weapons
Good VS: Battle-priests
Crusher ability: at +1 attacks with this weapon cause critical hits on 19 or 20. at +3 this is further improved to 18-20. stacks with class or race features that improve critical hit chances, like a champion fighter with this weapon at +3 could get a critical hit at 17-20
VS Battle-priest ability: at +2 gain resistance to Radiant and Necrotic damage. at +4 those are improved to immunity.

Battle-priest Gem:
Meant for: Cleric/Druid
Found in: Mace
Can be slotted into: any Bludgeoning melee weapon
Good VS: Inquisitors
Battle-priest Ability: usable as a Cleric or Druid Focus. any spells cast using this as the focus gain its bonus to spell attack and spell save dc. at +1 All healing effects and temporary HP applied by this player increased by 1d4. at +2 this increases to 2d4. at +3, 3d4. at +4, 4d4. this may be applied to healing items such as potions once during a short or long rest by meditating with the healing item while this weapon is equipped for 30 minutes.
VS Inquisitor ability: at +1 any Sneak attack damage applied to the wearer is reduced by 1d6 (so an enemy that has sneak attack 2d6 does sneak attack 1d6 against the wearer). at +2 sneak attack damage is reduced by 2d6. etc.

Inquisitor Gem
Meant for: Rogue/anyone with med-low AC really.
Found in: Scimitar
Can be slotted into: any weapon that has both light and finesse
Good VS: Defenders
Inquisitor Ability: at +1 add 1d4 to damage done with this weapon if you have advantage on the attack, or the target is adjacent to another creature that is hostile to it. at +2 increase to 2d4, etc.
VS Defender ability: if target has more AC than the user, add additional damage as above. this stacks with the above ability if conditions are met.

Defender Gem
Meant for: Paladin/Fighter
Found in: Shield
Can be slotted into: Shields, Medium or Heavy armor
Good VS: Spellswords
Defender Ability: add its current bonus to all saving throws
VS Spellsword ability: when hit by a ranged magic attack or magic missile roll 1d6. at +1 a 6 deflects the magic attack or 1 hit from magic missile, avoiding the damage. at +2 a 5 or 6 deflects the magic attack avoiding damage. 5 deflects 1 hit from magic missile, 6 deflects 2. at +3 a 4,5, or 6 deflects the magic attack avoiding damage. 4 deflects 1 hit from magic missile, 5 deflects 2, and 6 deflects 3. at +4 a 4 or 5 deflects the magic attack avoiding the damage. a 6 reflects the magic attack, changing the target to the caster, using the total of their spell attack roll against their AC. a 4 deflects 2 hits from magic missile, 5 deflects 3, 6 reflects 4 and deflects any remaining magic missiles.

Spellsword Gem
Meant for: Wizard/Sorcerer/Warlock
Found in: Short sword
Can be slotted into: 1-handed melee weapon or arcane focus
Good VS: Crushers
Spellsword Ability: May be used as an arcane focus. Adds its current bonus to Magic attack rolls, your spell save DC, and your damage to the spell if it causes damage.
VS Crusher ability: i toyed with having it have a percent chance to cast the shield spell when hit in melee, but i don't like that and am not sure what other effect to apply instead

what i would like from readers:

i would like opinions about the balance of these sentient magic items compared to each other and suggestions on how to rebalance them while keeping the flavor. do any of these seem significantly better or worse than the others, and if so how do i correct it? i would also like suggestions on different effects to apply to the items instead of the ones i have outlined. as i've had trouble coming up with some of them.

i often have issues presenting information, so please feel free to ask for clarification in some areas.

[Samot079]

It seems that you are off to a good start and I like the idea of having the sentient items be something you apply to an existing item rather than have the chance that they are something the players do not really want. I think the part that could use further thought is the defensive buffs against the other gems. I haven't played quite enough 5th ed to know the prevalence of flat damage immunity but the Crusher defense could scale for longer than all or nothing as an example, I'll create a list style for my 2-cents below:

Crusher: vs Battle-Priest(or even just in general would seem fine to my eye) +1 is necrotic resistance/+2 is radiant resistance/+3 is either necrotic immunity or advantage on saves verse it/+4 radiant immunity or save advantage

Battle Priest seems fine.

Inquisitor: I think its flat bonus could just be treated as sneak attack capping at 4d6 with +4 and improving existing sneak attack, for the vs. defender option since many rogue like classes don't get multiple attacks you could have it do something like adding an advantage dice to the attack for each attune step and at +4 instead of getting the fifth dice a critical hit requires a save vs death with DC of 8+Int Bonus+Proficiency or something similar.

Defender: vs Spellsword I think is the one that +2/+4 would work as advantage on saves vs magic and then resistance vs damage from spells, this coupled with save bonus from the gem might make it a bit more of a hard counter the spellsword than intended but I was aiming for simple interactions to recommend

Spellsword: vs Crusher you could have it proc a simple use a reaction for a 5 to 10 foot teleport or a reaction to take a disengage action at normal movement

Hope this helps your creative process a bit I'll check back on occasion if have you any questions on my thought process or would like further brainstorming.

[Kelik]

Crusher: vs Battle-Priest(or even just in general would seem fine to my eye) +1 is necrotic resistance/+2 is radiant resistance/+3 is either necrotic immunity or advantage on saves verse it/+4 radiant immunity or save advantage


how did you determine which resistance is applied at the lower level? in my experience death clerics have a lot of necrotic damage options as well as radiant options.


Inquisitor: I think its flat bonus could just be treated as sneak attack capping at 4d6 with +4 and improving existing sneak attack, for the vs. defender option since many rogue like classes don't get multiple attacks you could have it do something like adding an advantage dice to the attack for each attune step and at +4 instead of getting the fifth dice a critical hit requires a save vs death with DC of 8+Int Bonus+Proficiency or something similar.


i like the general ability being d4s just for balance, because a rogue getting up to 4 extra d6's in sneak attack seems really strong to me.

as for adding advantage die, i don't like the idea of more than one advantage die because there is no precedent for that in the standard rules at all, and it seems like all of that extra critical hit chance seems very unbalancing. but i do like the idea of adding a saving throw on a crit. maybe the following revision:

VS Crusher: on a critical hit the target makes a constitution save against instant death. the DC is your int modifier + the magic item's bonus + proficiency + 8


Defender: vs Spellsword I think is the one that +2/+4 would work as advantage on saves vs magic and then resistance vs damage from spells, this coupled with save bonus from the gem might make it a bit more of a hard counter the spellsword than intended but I was aiming for simple interactions to recommend


i'm pretty married to the spell deflect/reflect ability. its a magic shield. though i might just simplify the magic missile part into deflecting or reflecting the whole spell instead of individual hits.


Spellsword: vs Crusher you could have it proc a simple use a reaction for a 5 to 10 foot teleport or a reaction to take a disengage action at normal movement


i like the teleport. maybe i'll make it trigger before damage so the player teleports out of the attack, and have the range scale with the attunement level. something like +1 gets a 5 foot teleport, +2 gets 10 feet, etc. or maybe i'll have it be like a physical version of the defender vs spellsword ability, with the chance to avoid damage scaling up with a chance to counterattack at +4.

thanks for your input., any other input from yourself or others is appreciated.

[Samot079]

how did you determine which resistance is applied at the lower level? in my experience death clerics have a lot of necrotic damage options as well as radiant options.
On the damage resistance flow I was thinking more from a fantasy fluff perspective in general rather than specific mechanics, from book series I've read or otherwise resistance to negative energies has been more common than resistance to damage from divine sources so its entirely subjective based on the world history and forces at play.

as for adding advantage die, i don't like the idea of more than one advantage die because there is no precedent for that in the standard rules at all
That particular thought came from a recent video with Matthew Colville I saw on Geek and Sundry, the bonus advantage seemed a poor solution but advising on the Inquisitor gem is the most challenging for me since it seems the most unique in mechanics and rogue-like classes tend to fairly spiky damage output, perhaps the gem could also off skill bonus in addition to the damage or in place of it at certain attunement levels.

spell deflect/reflect ability
The all or nothing reflect will probably be simpler to implement and you could have it be something akin to save against the casters generic spell dc for the level of the spell with bonus or ability to reflect higher level spells based on attunement.