Help with some home brew magic items

[Wampyr]

So I’ve got some magic loot I’m gettin ready to drop over my next few sessions and I need help making it.

First: Firesoul Armor

This is just a few pieces of carved obsidian armor meant for the sorcerer in the party. I’ve been thinking of giving it an effect like magma shield from God of War but I’m still not sure.

Second: Diamond Sword of Demon Hell Made of Light Itself

The story behind the name is a bit hard to explain, but this legendary sword is expected to make an appearance. I want this to be really iconic but in all my searching for magic swords in D&D I’ve found mostly boring cliches.

Third: Staff of the Sun

This one is a staff of swirling white wood with a piece of Amber atop it. The PC possessing it currently doesn’t know this, but the staff is actually a root from a sentient tree and is still alive. Other than the “having a conscience” aspect I have nothing interesting for this item.

[Quoz]

Firesoul Armor: AC = 13 + Dex. 3 charges / day, recharges at dawn. 1 charge: shield. 1 Charge: Hellish rebuke. 1 Charge: gain immunity to fire until start of next turn as a bonus action.

Staff of the Sun: In combat, the staff always functions as under a shillelagh spell and uses the player's casting stat. It may also grow into any other hafted weapon (spear, lance, pike, ect) as a bonus action. The wielder is proficient. The wielder and up to 7 creatures in contact may teleport to the tree from anywhere on the same plane as an action. Allows 2 way communication with the tree, who can act as a mentor or warlock patron (fey?)

As for the sword, I'd need more to go on. If you're looking for a legendary blade that is unique and memorable, I would go with some sort of spell storing and release. +2 attack, damage, saves, and AC. All damage is Radiant. Whenever you successfully save against a spell or magical effect that targets only you, you absorb the spell into the blade. The blade can only hold one spell at a time. The next creature you strike with the blade must save against the same DC or suffer the stored spell's effects. No concentration required, spell lasts for full duration.

[Lord8Ball]

For the firesouls armor(studded leather stat), I'd probably do something like giving the wearer resistance against fire and giving it the effect of retribution which harms melee attackers for 1 fire damage and reduces damage against physical, piercing, and slashing by one. You could also go for the Pheonix sorcerer class ability which just goes charisma mod retributive fire damage on received melee hits. If your generous as @Quoz posted add a hellish rebuke in there.

For the staff, I'd probably give it abilities such as on command light, flaming sphere, and a modified daylight spell which does minor radiant/fire damage in a 20ft radius it would be like a miniature sun with a weak gust effect pushing you towards the mini sun simulating gravity. The actual sun itself is the size of a flaming sphere but has the same effect as a wall of fire and damage. Add charges as per a regular staff.

The sword could do something like as an action you can shoot a beam or radiant damage like a modified lightning bolt. Have a constant but nerfed effect of sickening radiance within 10 ft of the wielder. Why not implement this with @Qzos's suggestion.