Something I'm wondering is whether or not weapon artifacts can have over a +5 enhancement bonus? I'm assuming no as the DM's guide says no weapon can have over a +5 bonus, but I'm wondering if artifacts are the exception? Ultimately, I know I'm the DM and I can make it whatever I please, but I'm concerned about the balance.
Also, in case anyone is wondering here's what I'm thinking (I created it from scratch):
The Diamond Sword:
+5 enhancement bonus
Dragon Bane
Defending
Strength bonus +6
Constitution bonus +6
Deals damage as a large greatsword, but can be wielded by medium creatures (this comes from the hardness factor of being made entirely of diamond, plus it was enchanted to be lighter than it felt as well)
Once a day, the wielder chooses one of the following: Flaming burst, Icy burst, or Shocking burst. They also choose one type of dragon breath weapon and they gain immunity to that breath weapon for the day as long as they wield the sword.
Also, the wielder may choose a second breath weapon to use 3 times during the day.
The wielder may also cast any combination of the following spells 3/day as a 20th level wizard.
Fly, Cure Critical Wounds, Wall of Fire, Wall of Ice, Fear, and Trap the Soul*
*Trap the Soul can not be used when the artifact is first discovered by the PCs. As a soul is already trapped in the sword. The sword can trap up to a 12 HD creature/being/human.
The sword is also an intelligent item (the soul trapped within makes it so, long story, will explain later). Ego score of 30. Lawful Neutral alignment. 19 Int, 19 Wis, 10 Cha.
Lesser powers:
10 ranks in Intimidate, and Sense motive. Can use Zone of truth 3/day. And can use detect magic at will.
Greater powers:
Lesser globe of invulnerability 1/day, locate creature 3/day, dismissal on a foe 1/day.
Purpose:
To leave phylactery and return to waiting body.
History of artifact:
Long ago, the Purple Wyrm of Cormyr (the only actual purple dragon to ever have existed) sought to defy death itself. In human disguise he approached the world's greatest blacksmith. A dwarf by the name of Tordek Balderk. He offered the blacksmith a vast amount of treasure in return for forging the greatest dragon slaying sword the world has ever known. Tordek saw this as a challenge. One he could not refuse, as it would have brought shame to his clan. They were famous for accepting any and all challenges. Especially ones made in public...which this one was.
The Purple Wyrm presented him with the biggest diamond he'd ever laid eyes on, and was told to make a sword out of it. Tordek took the challenge and after 4 years of hard and intensive labor, he had finally crafted the greatest sword of his 378 year career (he lived to be 405 years old if anyone is wondering).
During the creation, the dwarf contacted a great wizard by the name of Mialee who he had adventured with for a short period in his life (short being about 50 years). Mialee put the powerful enchantments in place. These enchantments would mean the end of her life however. They drained her energy more than any normal spell would have and she fell ill during the process. She died three days after finishing them.
The Purple Wyrm was so impressed by it's craftsmanship, that he doubled the payment originally offered and blessed the Balderk clan and all it's descendants with a Wish spell.
After which, the Purple Wyrm took the sword back to his lair. There he delved into dark arts that only the most evil and vile of wizards research. He converted the sword using ancient techniques into also being one of several specially designed phylacteries. To complete the process, he had to steal many artifacts from other dragons. He became known as a famous adventurer while doing so. And by doing this, he made the diamond sword a weapon of legend. Famed for it's ability to bring down dragons in a single blow (...I never said the stories weren't exaggerated a bit).
By the time the Purple Wyrm had finished the process of becoming a Dracolich, he was attacked by a council of dragons (one of each type of dragon) who were infuriated and viewed the weapon he used as a betrayal of his kind (similar to the way a person who uses a dragon orb becomes hated by all dragon kind). If he had attacked other dragons without using the sword, no one would have cared or noticed. The council finally discovered the location of one of his lairs and while he rested in it, they attacked. Unfortunately, he did not have the diamond sword on him when they attacked. Upon his death, his soul immediately transferred to the diamond sword (the closest phylactery). The sword sits in the Purple Wyrm's main lair which is heavily guarded. The Purple Wyrm waits for the day an adventurer finds him. As he wishes to return to a body he prepared long ago (and is thus his special purpose).
If the Purple Wyrm ever leaves the sword, it ceases to be an intelligent item until the next soul is trapped within, or the Purple Wyrm is killed again and has to return to the phylactery once more. If a soul is within the phylactery, the Purple Wyrm can not use the phylactery if he is killed and must return to a different phylactery.
The sword can only be destroyed if Tiamat or Bahaumat throw it into the forge of Moradin. (In other words, you would need favored clerics of one of these deities to pray for a favor from their deity, but even if the deities grant the prayer, it will come at a ridiculously high cost to the PCs, from both the cleric and the deity).
The Purple Wyrm is a Lawful Neutral entity because it protected the region of Cormyr and it's royalty. Becoming a Lich seems evil, but he only became a lich so he could protect Cormyr for all eternity.
How the PCs find out about the sword: During Shieldmeet, a bard sings an old song about the sword, and confirms it to be true. How he knows...is anyone's guess. I'll probably find a way to make him a villain.
