A symbiotic item is basically an artifact that doesn't move on and hence may stay with the character throughout his career. In addition, the character's connection with the item (and the item's power) increases more slowly. The character must also meet certain prerequisites (generally linked to the theme of the item or the power) in order to use the item's new abilities.

When first found, Solar Radiance appears to be a +1 sunblade longsword (Adventurer's Vault). It gains the following abilities when its wielder meets the stated prerequisites:

Prerequisites: 5th level; you have performed a just or generous act in the presence of the sword.
Benefit: You can use the sword as a holy symbol.

Prerequistes: 7th level; you have used the sword to defeat an evil or chaotic evil creature of at least 6th level.
Benefit: The sword's enhancement bonus increases to +2.

Prerequistes: 9th level; you have used the sword to defeat a shadow or undead creature of at least 8th level.
Benefit: When the sword is used to deal radiant damage, add a +2 item bonus to damage rolls.

Prerequistes: 11th level; (to be determined)
Benefit: The sword gains the following daily power:
Power (Daily): Free Action. Use this power when you hit with the weapon. The target is dazed until the end of your next turn. If the target is evil or chaotic evil, the target is dazed (save ends) instead.

Prerequistes: 13th level; you have used the sword to defeat an evil or chaotic evil creature of at least 12th level.
Benefit: The sword's enhancement bonus increases to +3.

Prerequistes: 15th level; (to be determined)
Benefit: When you use the sword to attack a target currently marked by you, you gain a +1 bonus to the attack roll.

Prerequistes: 17th level; you have used the sword to defeat an evil or chaotic evil creature of at least 16th level.
Benefit: The sword's enhancement bonus increases to +4.

Prerequistes: 19th level; you have used the sword to defeat a shadow or undead creature of at least 18th level.
Benefit: When the sword is used to deal radiant damage, add a +4 item bonus to damage rolls.

Prerequistes: 21th level; (to be determined)
Benefit: The sword gains the following daily power:
Power (Daily): Free Action. Use this power when you hit with the weapon. The target is blinded until the end of your next turn.

Prerequistes: 23th level; you have used the sword to defeat an evil or chaotic evil creature of at least 22nd level.
Benefit: The sword's enhancement bonus increases to +5.

Prerequistes: 25th level; (to be determined)
Benefit: The sword gains the following encounter power:
Power (Encounter * Radiant): Free Action. Use this power when making an attack that targets AC. The attack targets Reflex defense instead. All damage from the attack is radiant damage.

Prerequistes: 27th level; you have used the sword to defeat an evil or chaotic evil creature of at least 26th level.
Benefit: The sword's enhancement bonus increases to +6.

Prerequistes: 29th level; you have used the sword to defeat a shadow or undead creature of at least 28th level.
Benefit: When the sword is used to deal radiant damage, add a +6 item bonus to damage rolls.

FireLance